I may be having a problem with mine. I reset it with the trip when I fill-up and the DIC indicates 24.7 and when I do it manually I get 21.8.

Now the DIC in the other GM cars I've had the DIC's were within 1-1.5 mpg of my manual calculations.

Just a shot in the dark here, but I'll give my opinion.

The DIC computes gas mileage based on the gallons used. You compute mileage based on how many gallons you pumped into the car. If you pumped in more or less than the car actually used you'll see an error.

I guess what I'm saying is you would need to start off with a topped off tank, then when you refill you would need to fill it up to exactly the same fill level to get an accurate number of gallons used.

Ray, I would try to run the calculation based on three or four tanks of gas to see if the amount of error decreases.

I also have noticed the DIC giving high ave mpg numbers in my LTZ. It is consistantly around 1 to 1.5 mpg too high compared with actual real mpg. I was beginning to wonder if anyone else has noticed this problem.

I was beginning to wonder if anyone else has noticed this problem.
I haven't done the comparision, but I will shortly. I zero'd one of the trip odometers at my last fill up.

I read a review of someone getting almost 41mpg - highway only in his 08 Malibu - may have been a rental - is this possible?

I read a review of someone getting almost 41mpg - highway only in his 08 Malibu - may have been a rental - is this possible?

Maybe with a strong tailwind.:D

The DIC in my GP was reasonably accurate enough that I stopped manually checking the MPG.

1 to 1.5 MPG off is pretty accurate considering, as pizza man said, it is using exact number of gallons used and you are going off of what you pumped in. At 21 MPG range, that is as little as one gallon of gas. I wouldn't be too worried about that. As long as you consistently calculate the same thing and it consistently calculates the same thing.

1 to 1.5 MPG off is pretty accurate considering, as pizza man said, it is using exact number of gallons used and you are going off of what you pumped in. At 21 MPG range, that is as little as one gallon of gas. I wouldn't be too worried about that. As long as you consistently calculate the same thing and it consistently calculates the same thing.

1-1.5 isn't bad and thats what I'vw been getting in other GM vehicles that I've owned. However, my Malibu has been nearly 4mpg off two different times.

What have others been getting on average. My wife is about 25% city and 75% hiway with her commute.

By the way chevEE that's a nice looking Camaro. I had a black 01 SS a few years ago and damn do I miss that car.

After 5500 miles of driving my total average is 22.4 mpg. I keep a log book and enter the information into a spreadsheet. Now with the better weather and summer gas the average lately has been around 24 mpg with a mix of 30 city and 70 highway.

Obviously the tank error is not an issue in my case since I'm keeping track of every fill up and this DIC is not very accurate. The DIC error is surprising to me since my other vehicles that I've owned which calculated avg mpg indicated lower than the real calculated mpg. Maybe I should start tracking the DIC avg in the log also to track the error to see how much it varies.

I have been doing mainly 80% city and 20% highway and I'm right around 22.3 mpg according to the DIC - hopefully as I drive a bit more highway over the summer I can raise that number...

I drive 95% highway, and manually calculate and log my fuel economy. So far the worst with the LTZ has been 25.8. The best 29.8. I expect this week's tank to break 30 for the first time (just over 3000 on it now). The DIC seems a bit optimistic, at about .5 - 1.5 over. This is also consistent with all but one past GM vehicle, that one being my 07 Avalanche. It was pretty close, being .5 under to .5 over most of the time.

I drive 95% highway, and manually calculate and log my fuel economy. So far the worst with the LTZ has been 25.8. The best 29.8. I expect this week's tank to break 30 for the first time (just over 3000 on it now). The DIC seems a bit optimistic, at about .5 - 1.5 over. This is also consistent with all but one past GM vehicle, that one being my 07 Avalanche. It was pretty close, being .5 under to .5 over most of the time.


This is great to know. I'm thinking about getting the LTZ but I'm a little leary about the 26 MPG highway rating. My GP is rated at 19/28 and I can get 25-26 MPG average with 75% highway/25% city driving. If I can get similar results out of the Malibu I'll be happy.

This is getting strange guys. I checked it again this weekend and the DIC was claiming 24.7 and I calculated 27.3. The car wasn't empty, I just topped it off since I was in town and only put in 5.6 gallons(153 miles on the trip).

I completely reset all info on the DIC everytime I fill up after I do my calculations. I reset trip A&B average mpg, average speed, everything. IMO a consistant 1 even 2 mpg high or low would be OK but a ± 3 mpg swing seems a bit excessive.

This is getting strange guys. I checked it again this weekend and the DIC was claiming 24.7 and I calculated 27.3. The car wasn't empty, I just topped it off since I was in town and only put in 5.6 gallons(153 miles on the trip).

I completely reset all info on the DIC everytime I fill up after I do my calculations. I reset trip A&B average mpg, average speed, everything. IMO a consistant 1 even 2 mpg high or low would be OK but a ± 3 mpg swing seems a bit excessive.

I think the average MPG shouldn't be reset. It's meant to give a long-term average. Of course, I'm only on my second fill-up (not including the free tank the dealer gave me).

At the moment my calculation for one tank for gas was 25.002 MPG, where the DIC was saying 23.4MPG.

I assume this is the same MPG monitoring system that is used in all GM models? Are other GM vehicles having these issues?

We had an 05 GTO, 07 HHR and our current 05 Silverado and all have been within 1-1.5 mpg consistantly and usually low. I figure the mileage the same exact way in this car and it's just off.

In fact I filled the truck up yesterday and calculated 18.2 mpg (406miles/22.3gallons) and the DIC was 17.4mpg average.

Someone's got to do some serious testing here. Since the DIC is also giving the trip mi's either the fuel use or the distance will affect the mpg result. Do we have any professional DIC checkers in the audience???? (On second thought someone should find the guy that came up with this acronym and give him a swift v8 knock to the head.)

DrD

I just filled up half a tank this morning because gas prices hadn't gone up at one station yet...

DIC told me 24.4, when I did the math, it came out to 25.1mpg on the V6 LTZ in mixed driving :) I'd guess I'm driving 65% hwy, 35% city.

This is getting strange guys. I checked it again this weekend and the DIC was claiming 24.7 and I calculated 27.3. The car wasn't empty, I just topped it off since I was in town and only put in 5.6 gallons(153 miles on the trip).

I completely reset all info on the DIC everytime I fill up after I do my calculations. I reset trip A&B average mpg, average speed, everything. IMO a consistant 1 even 2 mpg high or low would be OK but a ± 3 mpg swing seems a bit excessive.

The less gas you put in, the more margin for error. Run your tank all the way down and then calculate it.

I'd guess that the 26mpg EPA rating occurs when folks drive faster / more aggressively on the interstate (keep in mind it's the all-highway number). Like others here, I only get that or slightly less in more mixed driving. So far all of my mostly highway tanks have averaged over 28 (most over 29). I also drive strictly at the speed limits, so you can probably subtract 1mpg or so if you tend to go 5 or 10 over.

Calculating MPG based off of gallons pumped it at best a wild estimate. All pumps fill to different volumes based off the shutoff valve. The only way to get an honest measurement is to fill up at the EXACT same pump over the course of several tanks to compute the average. In my wifes Silverado, her DIC is always within .5 MPG of accurate. I have no reason to believe the Malibu is any different.

None are accurate my truck is off a couple MPG, every car or truck made are inaccurate they do it on purpose to make people feel like they are getting better MPG than they really are.

Non are accurate my truck is off a couple MPG, every car or truck made are inaccurate they do it on purpose to make people feel like they are getting better MPG than they really are.

I'm sure Chevy engineers spent lots of time trying to figure out to make thier MPG meter inaccurate to make the customer feel better :rolleyes:

In that case, they should make the oil life monitor read false early so that more people will come into the dealership more often for oil changes...

I'm sure Chevy engineers spent lots of time trying to figure out to make thier MPG meter inaccurate to make the customer feel better :rolleyes:
That's not too far fetched, impacted.

From the Chief Design Engineer of the Honda Ridgeline, the functions reporting MPG's were left off intentionally. Every driver drives differently, road conditions also vary from one driver to the next. Because of this Honda was concerned the AVG MPG display would alert each driver that the Ridgeline wasn't meeting the EPA mileage estimates and cause unnecessary dealership service visits.
In that case, they should make the oil life monitor read false early so that more people will come into the dealership more often for oil changes...
No car company wants to look "un-green" in this era.

I'm sure Chevy engineers spent lots of time trying to figure out to make thier MPG meter inaccurate to make the customer feel better :rolleyes:

In that case, they should make the oil life monitor read false early so that more people will come into the dealership more often for oil changes...

Then why is it that every GM I drive and I drive quite a few always reads high, always high never low. How is that?

I am not knocking the product just the MPG meter.

I respectfully disagree with your assessment of manually calculated fuel economy vs. the readout in the vehicle, impacted. Personal experience has proven this false. Simply put, if the variance in fillup amounts were to blame, the calculated values vs. the readings would average out over time (meaning, over several fillups). Instead, I find that the car's indicated readout is practically *always* higher than the manual number.

I won't go so far as to call conspiracy though. While this situation seems to be normal for most GM vehicles I've owned, the 2007 Avalanche was pretty close to dead on (enough that if it were my only vehicle with the DIC AVG readout, I might've agreed with you). It varied between .5 low and .5 high most of the time, with 1.0 being outliers in either direction.

In any case, I tend to call into account 'estimated' numbers based on fuel flow and current speed readings for the vehicle as the primary reasons for the inaccuracy. And even then, a 1.0 mpg optimistic readout is still only just over 3% optimistic on a 30 mpg vehicle. Not really all that big a deal, except that it's routinely that way, and I trust my lifetime manually calculated / logged numbers far better.

I respectfully disagree with your assessment of manually calculated fuel economy vs. the readout in the vehicle, impacted. Personal experience has proven this false. Simply put, if the variance in fillup amounts were to blame, the calculated values vs. the readings would average out over time (meaning, over several fillups). Instead, I find that the car's indicated readout is practically *always* higher than the manual number.

I won't go so far as to call conspiracy though. While this situation seems to be normal for most GM vehicles I've owned, the 2007 Avalanche was pretty close to dead on (enough that if it were my only vehicle with the DIC AVG readout, I might've agreed with you). It varied between .5 low and .5 high most of the time, with 1.0 being outliers in either direction.

In any case, I tend to call into account 'estimated' numbers based on fuel flow and current speed readings for the vehicle as the primary reasons for the inaccuracy. And even then, a 1.0 mpg optimistic readout is still only just over 3% optimistic on a 30 mpg vehicle. Not really all that big a deal, except that it's routinely that way, and I trust my lifetime manually calculated / logged numbers far better.

Ok, point taken.

My point was that say you drove 250 miles and filled up with 10 gallons. A perfect 25MPG. But lets say that you gave the pump an extra squeeze to make sure you're full. Now you're at 10.2 gallons, or 24.4MPG. What if the pump at station A stopped short and didn't fill you all the way up. Now, next time at station B you still drive 250 miles but put in 10.6 gallons. Now you're at 23.6MPG. It's totally forseeable. I do agree, however, that over a period of averages it may work itself out.

FWIW, my wife's Silverado is accurate to within about .5+/- if you factor in a .5MPG varaince. It's funny though... some people say thier indicator is dead on, others say it's not even close. :confused:

Then why is it that every GM I drive and I drive quite a few always reads high, always high never low. How is that?

I am not knocking the product just the MPG meter.

My 05 GTO, 05 Silverado read low consistantly. The Malibu is the 1st GM vehicle I've driven that reads high but it has become alot closer the last several fill-ups and is no within 1 mpg.

In any case, I tend to call into account 'estimated' numbers based on fuel flow and current speed readings for the vehicle as the primary reasons for the inaccuracy. And even then, a 1.0 mpg optimistic readout is still only just over 3% optimistic on a 30 mpg vehicle. Not really all that big a deal, except that it's routinely that way, and I trust my lifetime manually calculated / logged numbers far better.

Although it's possible that the MPG calculated and displayed on the DIC is erroneous, "current speed" is not taken into account when the displayed number is being tallied. "Estimated" fuel flow IS taken into account, however not in the fashion that most people would assume. Each vehicle is designed to operate at a specific fuel pressure, which is constantly monitored by the vehicle's PCM (powertrain control module or computer for those not familiar with the nomenclature). This input is not simply a "go/no go" guage (ie. yes i'm at proper pressure, or no i'm high or low), but a real time pressure reading. There may be SLIGHT variations in pressure, but it's fairly constant. The PCM also monitors the time that the engine's fuel injectors are open (again condition that is constantly monitored). With pressure known, fuel flow can be calculated on TIME based on injector discharge port size, and how LONG they are open. The amount of calculated fuel flow is then used in conjunction with final drive revolutions calculations to determine the vehcile's MPG (based on algorithms THOUGHT to be accurate considering all data available). IF the DIC is erroneous, its' errors should be CONSISTENT.

Just my 2 cents.

Just drove from Detroit to Milwaukee through Chicago - 400 miles. Hit construction in Detroit and Chicago. Also had to stop at 5 toll booths in Chicago. Fuel economy was 29.3mpg. DIC told me 31.1mpg Wish I matched the DIC info, but still pleased with the mileage.

Had the car locked in at 70mph with the cruise control

What it also could be, is a programming error in the Malibu's DIC computation.

I used to have a new Chrysler Sebring, and I found that when I coasted on the highway, it really skewed the numbers. Basically, the engine shuts off gas and then the computer adds an "infinite" amount of mileage to the average because they didnt properly capture the low/no gas usage. I was 4mpg high on the same Detroit to Milwaukee trip on the DIC on my Sebring, and then I talked to the guy who did the programming of the gauge at Chrysler and he explained why.

GM might have the same thing. I see it go to an instantaneous 99mpg all the time when I'm coasting.

I see that too (lots of hills here). But I've noticed that it isn't necessarily at 99 all the time- it varies anywhere from 34-55-60 etc. the whole time I'm coasting. Seems like there are a lot of variables that would make it hard to be exact in the computer, so I'm fairly happy that I can use the DIC readout for an idea of when I'm doing better or worse, and tracking the actuals on paper.

I've got 5000+ miles on my 08 malibu and I think only once has my manual MPG calculation been less than the DIC. My manual calculation is almost always better than what the DIC says and I fill up at the same station 90% of the time (although not always the same exact pump).

I don't recall the exact difference, but I'd say my manual calculation is anywhere from 1 to 2 MPG better than the DIC.

One one trip between Columbus and Mason (Warren County), Ohio I traveled 239 mi. roundtrip in the Malibu (LS 1FL with the 3.5L V6). 80% freeway/20% urban and suburban arterial routes.

Filled up the tank with 7.2 gal of fuel, for a theoretical fuel economy figure of 33.19 mi./gal.

This is what the DIC indicated when I stopped at the filling station. I think the DIC figure is more accurate in this case due to the fact the fuel tank was already a bit over half full at that point.

So I'd say the DIC is pretty accurate indeed.

http://home.comcast.net/~troy805/Malibu4.JPG

I think there is a real problem with all these people who are so self conscious about their DICs! I mean stop looking at your DIC and drive your car! No amount of looking at and then fiddling with your DIC will make it any better. Just face the facts people. Some people have better DICs than others.

Or more LEAD in their shoes :D:D:D

You got 32HWY w/ the V6?!?!? I got the 4 and the one long road trip I took it on it averaged about 30 and I thought I was being conservative with my driving habits.. are you hypermiling????

Hahahahaha :)

I think there is a real problem with all these people who are so self conscious about their DICs! I mean stop looking at your DIC and drive your car! No amount of looking at and then fiddling with your DIC will make it any better. Just face the facts people. Some people have better DICs than others.

I'm happy with my DIC...........

I don't know if you ment to or not but this is a funny post I've read here. Or maybe I've just got a dirty mind.

I'm happy with my DIC...........

I don't know if you ment to or not but this is a funny post I've read here. Or maybe I've just got a dirty mind.

I look at and fiddle with my DIC all the time.
I'm sorry, I'm sorry. But it was just too good of an opportunity to pass up. :D

Gotta be careful...I got an infraction on GMI today for calling a guy an idiot...didn't mean it, of course, but still looked bad on my part.

I think there is a real problem with all these people who are so self conscious about their DICs! I mean stop looking at your DIC and drive your car! No amount of looking at and then fiddling with your DIC will make it any better. Just face the facts people. Some people have better DICs than others.

BEST POST EVER On any forum anywhere. SDB1 you are king.

I honestly can't stop laughing.

I'm happy with my DIC...........

I don't know if you ment to or not but this is a funny post I've read here. Or maybe I've just got a dirty mind.

I couldn't help it and am surprised it hasn't already been said.

To add to my earlier post.

Even if you think there is something wrong with your DIC. I highly suggest not showing your DIC to other people. They may get jealous just looking at your DIC and realize their own shortcomings. If you show your DIC to your dealer make sure that the mechanic is gentle when handling your DIC. Just a warning!

Anything to add?

Never take a picture of your DIC and put it on the internet, no matter how impressive it is.
You may get some unwanted attention.
:D :D :D

http://home.comcast.net/~troy805/Malibu4.JPG
Oops. Too late!

^^^
I've been deluged with e-mails from ladies I've never even met ever since, commenting on my... well, you know... :D:D:D

If your DIC isn't working right, then this forum is NOT the right place to discuss it.
:D