Idrive a Cobalt SS/SC. Car runs fine but at WOT around 5500 rpm car starts to not pull to well. What could this mean?

 

Clogged cat my guess

 

Does it sputter? CEL? Knock? Boost drop?

Joel

 

It sputters and then doesnt really pull

 

How old are the plugs and what are they gapped at? Is it kind of like hitting a rev limiter when it sputters?

Is it over boosting? (That would be clogged cat like the guy above said.)

Any CEL's?

Joel

 

Not sure what they are gapped at but i have almost 20,000 miles on the spark plugs.

 

Pull them and check them. If it isn't over/under boosting and no CEL's I'd say start with plugs.

Joel

 

yea no CEL or boosting problems

 

if pulling them..change them it cheap. gapem at .035 or lil less. If it was kr it would have to be alot for Ive seen knock on my gauge somtimes but never feel it or the random misfires that happn every so often.

 

fuel or spark.. most likely spark.

 

SOOOO did we ever figure this one out? Mine just started doing the same thing.

 

nope but i went to change my plugs today and whoever owned it before me stripped the hell out of the cover over the plugs so now i gotta drill the stupid things out

 

Bad injector...

 

check your wiring to if one slightly loose it will cause this had this problem with my friends so check that too

 

At first I thought it was bad fuel. Now, I am having second thoughts.

 

your car is broken, sell it to me for $500

 

Spark knock or High iat's causing it to pull timing

 

What about Part Throttle @ 5500 RPM?

 

car cant over boost

 

Your right, it's cleary never happened before and there is not a recall on the cat for it.

Joel

 

It was my plugs!

 

Close the gap on those plugs.

I run a mostly factory engine with NGK copper, and the factory gap doesn't work well at all. I like them @ 33-35. I gapped them @40 to see what would happen, wow what a difference..

 

Good to hear

 

Factory gap on my 07' was 0.035".

The gap in the manual is crap.