Help in Diagnosing problem with '07 Malibu

[heights 222]

Hi, My 2007 Malibu LS 2.2L struggles to run when engine is cold. In the winter I always warm the car up before leaving but lately even after I do that it still struggles to run but once its completely warmed up it runs alot better but it will struggle to accelerate to gain speed and/or trying to pass another vehicle and going up hills. It also has a non-working fuel gauge.
Its like it can't get enough air or gas or something. Once I turn the key I can hear the fuel pump working and once i start the car it idles fine, in fact its so smooth and quiet its hard to tell if its even running

I took the car to Auto Zone and they put the scan tool on and it threw a code about the fuel sending unit. It apparently has a "bad electrical connection at the fuel level sending unit, probable cause failed fuel level sending unit."

I took the car to a mechanic a few weeks back and they did a quick scan on it and all that was found was that it needed a tune up so I had them do that. They replaced the spark plugs, coil boot(?) etc... which really didn't help much as its still struggling to run.

The car has just over 100,00 miles on it

So now this brings me to this forum in hopes to find possibilities i could try. I'm totally at a loss. Anyone with any ideas?

I think I'm going to invest into a scan tool

Thanks!

[DrivenDaily]

Check the catalytic convertor.

Also see if you have an EGR which can cause similar issues.

O2 sensors replaced anytime recently? They're usually good for about 100K miles.

Do you keep getting gas from the same place? You might be getting water in the fuel or some other garbage and need to change your fuel filter.

When was the last time you checked the air filter? Clogged AF can do what you say.

So many things to check - some easy, some not so. Come back and tell us more...

[Drunken Elvis]

Check this site http://www.carcomplaints.com/Chevrolet/Malibu/ for recalls and tsbs relating to your car. You will find the fuel pump and gauge problem is well known. It might help to mention these tsb and recall numbers to a dealer if choose to take it in.

[heights 222]

Originally Posted by DrivenDaily

Check the catalytic convertor.

Also see if you have an EGR which can cause similar issues.

O2 sensors replaced anytime recently? They're usually good for about 100K miles.

Do you keep getting gas from the same place? You might be getting water in the fuel or some other garbage and need to change your fuel filter.

When was the last time you checked the air filter? Clogged AF can do what you say.

So many things to check - some easy, some not so. Come back and tell us more...

Wow thanks for the list! That should help alot. Thats quite a bit of stuff but like engines these days there could be a million things it could be

To answer your questions: No I get my gas where ever I'm at at the time. i keep it on full most of the time because of the gauge not working.
I just changed the air filter about a month ago when I had my oil change. I get regular oil changes and they keep an eye on my filter, wipers, lights etc...


I have a question for you, Would a non working fuel gauge and sending unit if bad would cause the engine not getting enough gas through the system? I am about to replace that soon as I was suspecting that is the problem, Am I right? plus it would be awesome to have a working gauge again and stop worrying about running out of gas!

Thanks a bunch for your help with this I certainly appreciate this alot!

[heights 222]

Originally Posted by Drunken Elvis

Check this site http://www.carcomplaints.com/Chevrolet/Malibu/ for recalls and tsbs relating to your car. You will find the fuel pump and gauge problem is well known. It might help to mention these tsb and recall numbers to a dealer if choose to take it in.

Thanks Elvis I appreciate the link. I will defintely check it out, i think I have heard there was recall issues with the Malibu.

[DrivenDaily]

The only way that I can think of where a non-functioning or intermittent fuel gauge and/or sender would cause any kind of driveability issue would be if the fuel pump wiring or connector has also been damaged or compromised in some way. They are separate systems (sensing vs supply) that merge at the tank.

[heights 222]

Originally Posted by DrivenDaily

The only way that I can think of where a non-functioning or intermittent fuel gauge and/or sender would cause any kind of driveability issue would be if the fuel pump wiring or connector has also been damaged or compromised in some way. They are separate systems (sensing vs supply) that merge at the tank.

Very good thank you Driven, many thanks!

Take Care

[ElantraMax]

I forget, Does that engine have a Idle Air Control Valve? That is a Common problem on Alot of cars. That will cause a Hard Starting, Stall condition at idle.

[heights 222]

Originally Posted by ESCAPEMAX

I forget, Does that engine have a Idle Air Control Valve? That is a Common problem on Alot of cars. That will cause a Hard Starting, Stall condition at idle.

Well, I'm not sure. These Ecotech engines are complicated to say the least IMO but its a nice smooth quiet engine, that i do like
But I'm not really having the issues with hard starting and stalling at all. It's idling smooth but just alot of resistance getting up to speed and going uphills is a battle. I just try to hold steady and be patient lol!

Thanks for your help, much appreciated.

[heights 222]

Oh btw, I've decided after doing alot of research that I am hoping my hunch it right and going install a new fuel pump this weekend. Fingers crossed!

I will try to get back here and report my findings, Thanks to all of you!