[Brian20081978]

Looking for any help on this issue. 2.4 echo tec. 2010 Malibu runs great except when it sits overnight. When It sits overnight it then has a very rough start for a minute or so but then runs great. I’m thinking leaky injector that is dripping inside the cylinder. Just wanted some advice before I swap the injectors.

 

[ma7amad]

cold start is always hard in winter time specially when car sits for long hours, you can check the tail pipe for smoke mixed with vapor or some grey color with un burned fuel smell, that indicates fuel not burned in one of cylinders due to ignition problem like misfire (no or weak spark) or over fueling condition due to leaky or sticky open injector. better to check for ignition system first then move to injector testing. although i recommend injectors periodic maintenance they are prone to be clogged and should be inspected after this age.

 

[DrivenDaily]

Search CMF and/or Google for "Top Tier Fuel". Using 'mom and pop' fuels could cause a build-up that prevents an otherwise good injector to not fully close, yet still run well once started.

As a DIY remedy, Chevron's Techron has always proven to be a good cleaner, but there are other brands. What you need is an ingredient called PEA (polyether amine) to help do the work.

 

[repairman54]

Gumout also makes a cleaner w/PEA. I'd run a couple tanks of gas with a heavy dose of cleaner first before replacing injectors. The minute or so of rough is when the ECU is in open loop until the O2 sensor heats up and takes over. Does it have to crank a lot before it starts ? That's the sign of a leaky injector, excessive cranking until it fires up. Also MAF sensor could be sensing colder intake air temps making a rich mixture on start or ECT could be sensing a colder engine than what it really is doing the same. Injectors are not a common fail part but are first on a swap out without advanced scanner diagnosis. I'll add properly gapped fresh plugs also, worn open gaps will hurt cold starts.
P0172 CHEVROLET Possible Causes

• Faulty front heated oxygen sensor
• Ignition misfiring
• Faulty fuel injectors
• Exhaust gas leaks
• Incorrect fuel pressure
• Faulty Mass Air Flow (MAF) sensor

 

[Javier Tlacxani]

Any updates, did the cleaner additive work I just bought a 2010 malibu 2.4 and I have the same problem I have new plugs, cam sensors and vvt solenoids since i had codes for this sensor i thought that was the problem but after i replaced them i still have the cold start

 

[cp-the-nerd]

Any updates, did the cleaner additive work I just bought a 2010 malibu 2.4 and I have the same problem I have new plugs, cam sensors and vvt solenoids since i had codes for this sensor i thought that was the problem but after i replaced them i still have the cold start

Are you getting P0172? It's probably the MAF sensor or bad wire connection to it.

 

[Javier Tlacxani]

No codes or engine light this morning my wife crank it and it was really rough it cut off on first try and she had to re start it and push the accelerator after it crank we have some smoke coming out the tail pipe any ideas please...

 

[cp-the-nerd]

@Javier Tlacxani given that we have almost nothing to go off of, the first thing you should do is get the rough cold start on video. You can post that here, but more importantly that's something you can show to a mechanic.

 

[Mastersparz]

I had the same issue with my 2010 Malibu 2.4L Flexfuel. Hard starting in the morning, after it started it ran great. After a few weeks, I had narrowed it down to the ethanol content calculation done by the computer. That calculation was wrong and causing over fueling on cold start. So the dealer had to reset my ethanol content calculation.

 

[cp-the-nerd]

I had the same issue with my 2010 Malibu 2.4L Flexfuel. Hard starting in the morning, after it started it ran great. After a few weeks, I had narrowed it down to the ethanol content calculation done by the computer. That calculation was wrong and causing over fueling on cold start. So the dealer had to reset my ethanol content calculation.

Thanks for the helpful suggestion! That's good info.

 

[cmh08201975]

Looking for any help on this issue. 2.4 echo tec. 2010 Malibu runs great except when it sits overnight. When It sits overnight it then has a very rough start for a minute or so but then runs great. I’m thinking leaky injector that is dripping inside the cylinder. Just wanted some advice before I swap the injectors.

I have the same car and the same problem. When it's warm outside car starts and runs fine. Cold weather when car sits over night I have to push the accelerator to the floor to get the car to start then ill smell gas like its flooded once it starts and idles for about 15 secs she runs great. I've changed the throttle body maf plugs and coil packs battery is less than 2 yrs old im lost at this point

 

[Drunken Elvis]

If I was to throw parts at it, an Engine Coolant Temp sensor would be my guess but I would rather give that money to a diagnostic garage.

 

[cmh08201975]

If I was to throw parts at it, an Engine Coolant Temp sensor would be my guess but I would rather give that money to a diagnostic garage.

Yeah I had an appointment to take it to the dealership but it was like a month away and I forgot all about it. Then it became summertime and the hard start went away. I've already thrown plenty of parts at it to no avail. The bad part is that the dealership usually wants you to leave the vehicle overnight and I have no other vehicles.

 

[blague]

I have the same car and the same problem. When it's warm outside car starts and runs fine. Cold weather when car sits over night I have to push the accelerator to the floor to get the car to start then ill smell gas like its flooded once it starts and idles for about 15 secs she runs great. I've changed the throttle body maf plugs and coil packs battery is less than 2 yrs old im lost at this point

I have the exact same problem, did you figure out what the fix was??