Hello Fellow Cobalt Owners,

I have had a problem with my SS S/C from day one. I've run searches on this several times in the past only to never truely find the solution. For reference, my 2006 Cobalt SS is a GMPP Stage 2 car otherwise unmodified.

My problem is a hesitation under acceleration. Moderate to mid-level throttle, this hesitation feels like a misfire but has never caused a check engine light in its 36,000 miles. The feeling seems to clear up once I get the rpms up enough. The feeling magnifies once you get some weight in the car. This is not the low speed idle surge.

This problem also existed before the Stage 2 install. I know this for certain seeing as how I thought it was a programming issue that the Stage 2 tune would clear up once it was installed. The Stage 2 was installed at around 7K miles.

My Cobalt has had several items replaced in attempt to solve the problem; both exhaust sensors, the ECM, and the entire engine.

Being that I am a Chevrolet dealer, I have had all of GM's resources at my disposal, so I can't blame myself for not trying hard enough!

One strange item to point out was after the new engine was put in. When we called to get authorization for the Stage 2 tune from GM, they said that it no longer requires one, and yet my car still revs up to 7K without fuel cutoff like the tune is supposed to allow.

None the less, tune or not, this car has never run right.

I've since heard of some people saying that colder plugs have helped, but not much else.

Has anyone been able to resolve their hesitation issue?

Thank you,

~Lew

 

Only need to post this once...

 

Well, I think I am having a similar problem with mine. I have a 2007 SS/SC 17000 miles now with stage 2 installed. I noticed it before I did upgrade, and was told the new computer flash would probably make it go away. NO GO! I notice it does it just normal everyday driving, in 2nd gear just about to shift to 3rd, (RPM's never matter). The boost gauge is always about 4-5 psi when it does it. I havent had a real problem with it till a little while ago, I was racing and it did it when I was floored. I have had it in the shop about 10 times to try to figure out what was going on. All they can do is wait till it throws a code and tell me to go away. I dont blame them for being sick of me, but I want it to run right. I know how to drive my car VERY well, I have never heard anyone else having this prob, but it is very frustrating!! Anyone have a clue?

GM says no other complaints of this prob. Head GM guy is baffled!

Me too!

HELP!!

 

Hey, mine has done this to, several times, only with mine, the car dies and the gauges shut off and the car wont even idle, maybe for 3 seconds. Even then its at 200-300 rpm. They dont know whats wrong with mine either. Once it threw a code and they replaced the crankshaft position sensor and it still did/does it.

 

Sounds like we're in the same boat.

Did your dealer acknowledge that there is a problem?

Please let me know if you have any luck on your end!

Thanks!

 

weak fuel pump? fouled spark plugs? weak coils? ...there could be alot of reasons

 

Also check your intake manifold coolant. There could be air leaks in there from after the engine install. I had this problem after installing the dual pass. It was like a misfire everytime I got into boost.

 

go clean your MAF could be that... also go buy a intake its prolly cuz of your stage 2 this happens usually in your second gear right?? If so buy a intake it will lean the car out alot

 

He said it happened before he had stage 2. My guess would be sparkplugs. Had a similar sounding issue myself. I got the NGK BKR7e's from CA for 15$ shipped, and after 3 adjustments on gapping, problem solved. Worked for me so I'd recommend you check the plugs and maybe play with the gap.

 

I also have this problem. Still troubleshooting. Will post if I get it figured out.

Some background:

gm stage 2, injen cai, ngk BKR7E, dual-pass

hesitation occurs occasionally at wot or heavier than normal acceleration. It seems to happen more often when the car has been run for less than 30 minutes or so. If i've been driving around all day, then I do not notice any hesitation at all.

I also see some knock retard via my interceptor during wot in 3rd gear or higher but does not appear related. (going to try adding a qtr tank of race gas to raise octane level for this prob) not related meaning I have felt this hesitation during a knock-free acceleration.

I also should note the hesitation is felt with 3 different pulley sizes: gm stage 2, gm stage 3, and nates 2.9

EDIT:
two more things to mention.. 1. I did NOT have this problem before stage 2, dual-pass install and 2. I am still waiting for my replacement CPS to arrive at the dealer (not sure if this could be it or not)

 

I feel this hesitation also. It bugs the hell outta me. I plan on getting a full zzp exhaust via the zzp group buy here in a few weeks though and hopefully that'll clear it up somewhat. I notice it the most whenever I run 89 octane fuel in the car. With premium gas being a few cents shy of $4.00 down here, I save it for the weekends

 

how many times are people going to say this..........."put on a smaller pulley or intake." this won't lean your car out, unless you are maxing out the injectors. The computer has been programmed for specific A/F ratios.

Why do people keep saying this.........?

 

Its obvious if enough people say it it may become true JK

 

your either onto something, or your on something.

 

Well I cleaned my MAF sensor today. As I was putting it back in I noticed a nice slit in the tubing on my injen cai. aHAA! This must be my problem. I've ordered a replacement already. Will post if this solves my problem. I would think extra unmetered air would be the cause of my hesitation problems. For now, I covered the hole with duct tape and wedged a rag in between the tubing and the frame to prevent it from cutting through the tape. Lovely.

 

I was having that problem with mine. I was stage 2 at the time, the dealership was no help. I cleaned out my throttle body with a toothbrush and cyclo intake cleaner. The problem went away after that. a can of intake cleaner is like $6 max, so it is worth a try. If you do it have the key in the run position with the car off. Then have someone hold the gas pedal down to open the throttle plate so you can clean both sides of it.

 

Get your car tuned. Remove the PE delay, clean up your maf and ve table, and get all your settings tweaked.