I have a 2006 Cobalt SS with GM Stage 2 and 2.8". Also running K&N intake, GM header, Corsa exhaust, and colder copper plugs. I have just 12k miles but I admit I run the car pretty hard.

The problem I am seeing is new. During a WOT run to redline in 2nd or 3rd the car will "stutter" close to redline, the engine light will pop on, and the engine will die. The first time it happened on the highway the car would not restart. Dealer replaced the crankshaft sensor and the pigtail to the sensor but the problem is still surfacing. OnStar diagnostic says it is an "ignition problem" and to see dealer, blah blah blah. Any ideas? My faith in this cars reliability has been shaken.

I have noticed that I am seeing more boost lately, like 17-19psi by the gauge as I run to redline. I am wondering if I am getting too much air? Maybe the Stage 2 program is shutting her down?

Thanks in advance!

AK

 

find out what the code is from the CEL and repost.

 

Sounds like your Catalytic Coverter is plugged. If you are seeing more boost, it is most likely due to a restriction caused by the clogged Cat.

Disconnect your 2 oxygen sensors, and remove the cat.converter and look inside.

Seems to be a common problem.

Good Luck!

 

if its throwing a ingnition code,i doubt its a cat, it would probably throw a caltylst efficincy code, P0420

 

fouled plugs or detonation is occuring. check your plugs.

 

I don't think it's the cat. That was off the car not long ago and looked fine.

I will hook up a Tech 2 and pull codes this afternoon and post. Last time no code was stored. I have seen codes in the past from the MAF: signal out of range but, I figured that's just a byproduct of K&N.

Any other ideas? Could the plugs be shot in 12k miles? I pulled them at 10k and they looked good.

Other ideas?

 

Possibly - but I would have a look due to the boost spiking so high - your cat might be starting to plug up - and it could be causing ignition problems at red line (boost spike).

Check the gap on the plugs also - that could be contributing to the problem.

 

if you're still running stock plugs you might want to change them and get 1 step colder since you've got a 2.8.

If your car fully turns off and shuts down then it sounds electrical, but only the engine gods can say whats wrong at this moment, once you get a code then it could be looked up.

 

i would change your plugs with every oil change on the 1 step colder ones. they are going to expand with all the heat we put in our engine. change em lower the gap another mil and take a run. see if that fixes it. CHeck your codes too

 

What is your AFR when getting close to redline? Are you getting knock? Sounds like you are running lean. The higher boost maybe due to the fact that I bet it is cold as **** up there in CT which could be contributing to the car running lean as well.

 

Only the engine shuts down so I don't think this is related to a larger electrical problem.

After running thru 1st, 2nd, and part of 3rd at WOT the tach dropped to 0. Luckly, it restarted but the first few tries sounded pretty bad, like the timing was off. Strong smell of gas in the car before it fired and I was able to limp the rest of the way home. Ignition is the likely suspect but where in the electrical system to look is the question and why is it happening?

AK

 

I only have a 2.9 right now, but my plugs foul in 2k miles...whether I'm driving hard or not. Its running insanely rich. I also ran colder plugs, but I've been replacing with stock plugs.

You should take a plug out and post a picture of what it looks like.

 

seriously pull your plugs and look at them. i bet 1 is melted or you will see signs of fouling and detonation

 

I'm calling it, COT...

 

that is another possibilty but it really sounds like a plug issue.

COT would be affection the whole run im pretty sure

 

this just happened to me cheeked my NGK plugs and there were no good cheek yours fixed mine!!

 

you know, there is a flash for MAF perfomance recalibration

 

really??? dealer available? where?

 

yup. but that will only work on the stock tune. not staged

 

I believe thats only if you have an old stage 2 tune and have a certain lean code that constantly gets thrown. I doubt that this would affect his car in that way. Otherwise i'd expect a mandatory reflash if GM ever realized the problem was that bad. I have one of the first (first batch ever sold to public) stage 2 tunes on my 2005 and haven't had any problems like that, but i did change my plugs once i got a 2.9" pulley, intake and exhaust at around 13000 miles (this past summer).

 

yeah your right aswell there was the one for stage 2 but talking to dealers it was fixed quickly once they noticed it