well first off let me tell every one what is done to my so they know i have a k&n cold air intake, gm stage 2 kit and a cobalt addiction 2.79 pulley. and ngk colder plugs gapped at i think but cant rember 35. to 40 gap. here is the problem i am having when i am at wide open throttle at about 5000 rpm the car starts to miss fire or hesatate dont know witch it is but it feals like it is missing and is very sluggish. the supercharger is also breaking up the sond that is lol when im on it. now also this started when it got colder out like down in the 40s. it also looks like it is running more boost. you know how the boost guages are on these cars lol. its just over 17 pounds but usually when im on it when it is running normal its bearly over 15. and with stage 2 pully it was just under 15 pounds. now my question is could it be the plugs. the new pully. or even the cat being cloged up. becase sometimes i can smell a burnning smell when i get out of the car. so any help or ideas would be great thaks guys.

 

good chance it could be the cat. i've heard of a few that have had clogged cats after a stage 2 upgrade

 

yeah it could be the cat. I would put the stock airbox back on, then put the stage 2 pulley back on and see how it runs. If you are still having the same problem I would take it into the dealer and have it fixed before you blow something up.

 

Its colder outside bro, you might want to get a new tune for the colder weather.

 

what tune would i need. should i have gm give it the new so called reflash if that is even true

 

just bang out the cat

 

If this is the problem:

when i punch it pulls great midrange till about 5500ish then kinda falls flat and the supercharger whine starts stuttering.. bare with me here....

EEEEEEEEEeEeEeEe <---- thats the sound


is something wrong or are my injectors maxed and im bleeding boost? im running 2.8 with stage 1 kit


this is the solution

It's bleeding boost. Not because of how much pressure there is, but because of TQ management. It is calculating that you are making too much TQ, so it starts limiting boost and timing, making the car fall on its face. I know from experience. My car made the same noise, and people were telling me it was belt slip, or that the bypass was blowing open, well I bought a smaller belt, over sized pulley, and it didn't fix it. I clamped the bypass closed and all that did is throw me into limp mode. So then I took a second look at my tune, and saw that I forgot to get rid of ALL TQ management. Got rid of it, problem solved, picked up 5mph in the traps (Not my car, but NoRemorse's post)

so you can either get it tuned or do the bypass mod which is free

 

stotte20; I am not a great wealth of information, but I can say this much: I have had similar problems with mine. I got the stage 2 w/flash; plus an AEM CIA; GMPP Cat-back sport; and intense 3" cat-less down pipe and all was well. After I put on the C'A 2.79 my car was pushin 17-18 boost. Then one day Barreling onto the interstate I backfired and I have been pushing 12.5 ever since. I reset my PCM all the time w/ no change. I installed the NKG's -1's, runs smoother but w/ same boost... Maybe that "Mase" is right it could be the TQ managment... PS its warm in my state so I have no feed back on the NKG's in reference to cold weather.

Got to go... I am at work... Good luck; I will get a tune this month so if I learn anything I will post it.

 

I've got a similar setup, stage 2 with a 2.8, bkr7e's gapped at .35, full exhuast, and a custom tune. The car ran great the rest of the summer after the tune (still in the '80's around here ), but ever since I drove up here to Atlanta yesterday, I've been showing as much as 5 degrees of kr above 4k rpm's (won't push it any higher than that right now) and ignition advance averaging high 30's cruising on the highway. The shop was 98 F when my car was tuned, and last night here in Atlanta, it got down to 51 F. I'm guessing the tune was too aggressive for the colder weather or, most likely, the stage 2 injectors just can't keep up with the much cooler and denser air. 60# injectors and a new tune are going to be high priority when I get back home.

 

the so called reflash is in fact an updated tune and can be confirmed with any compitent gm tech. give it a try what do you have to lose other than some time to take care of your car.

 

thanks every one for the help now i have to go try all these things lol spend some money on a tune or injectors lol

 

personally i don't think it's injectors. i would go with the tune and the stock plugs and see where it takes you before you spend a few hundred on injectors. when they do the tune they would also be able to tell you if you are maxed out on you duty cycle for the injectors

 

Stotte20: After writing you, above, on the first; I thought about how much carbon had built up on my exhaust tip; then about how much carbon could be in my engine. I then went and bought a $2-3 bottle of STP fuel injector cleaner. Drove home (30mi.)... The Next morning I was boosting back in the 15 range, 12 since the back fire, and have been ever since. I only have 5500+ miles so I never considered this common task I would ussually do with almost every car I ever owned. (((Just a thought)))

I realize this post is a couple days after your last post and may not be read, but I thought it may help. I think sometimes I get to caught up in doing stuff to cars that I don't remember to maintain the car itself... and I'm 33... maybe I'm a little DEE, DEE, DEE!

 

thanks man i will go get some of that stp cleaner and see if it works. you know why the hell not. i put back on my stage 2 pully and it dont miss fire as much but one i get to about 6000 rpm it starts missing and hicuping. so ill give this a try and check my pulgs if not then off to the dealer i go.