ok so i have been having problems with my dearest monte...first i had a 4 inch spectre filter that one, clogged up the hot wire maf sensor and ruined that and two, sucks in WAY too much air and made the pcm command rich but couldnt compensate enough so it was lean still LTFT is at -12% but its heating up and having lean symptoms. When its on the road and you open it up it goes to 4 grand and doesnt go anywhere until you let off the throttle i replaced the maf and put the stock air box back in. now it stumbles and occasionally dies at idle under load or at a stop. Im almost possitive its good now but it just needs to reset the fuel map that is built into adaptive strategies anyone know how to do that? i have the battery unplugged so hopefully that will work but i know computers hold info well even without power. a thought also crossed my mind about o2 or cat? tell me whatcha think

 

if its running lean that shouldn't hurt the cat too bad but rich will destroy it fast. i'd be concerned about an intake leak on the UIP. it should never matter how big a filter you put on because the throttle body will only allow so much air into the intake. the MAF sensor has been replaced correct? to find a vacuum leak run the engine at idle and spray throttle cleaner around the intake gaskets vacuum lines and anywhere after the MAF. do this when the engine is cold startup because you don't want a fire to start off the manifolds when its hot.

how many miles/kilometers on the car because the cat is a very likely cause of what your experiencing. it just doesn't explain lean condition you could have 2 issues going at the same time.

 

Wish I could help you bro but i'm about as dumb as a bag of rocks when it comes to mechanical stuff

 

117k i am almost positive there isnt a vacuum leak bcuz it would have to be large for this and then you would also notice it in your brakes and other vacuum assisted items but right now after a start from cold if i dont give it gas it will die out and when it finally stays up it sits above 2000 its warm in under 5 minutes which would make sense with a clogged exhaust and theres a rattle in the pipe as if the cat pieces broke off and are in the pipe...hand at exhaust its just warmth no cylinder pumps

 

Just throwing an idea out there... Is there any chance of a leak before your MAF? I mean between the TB and MAF?? Not even sure this would cause it but its an idea.

 

not really i put the stock air box back on for one and also it wouldnt explain the stalling when under hard acceleration

 

from what you have said it sounds like the cat is pooched and i would still test for vacuum leaks or maybe you have the melted egr port in the UIM problem.

 

well the cat is off now and same ****...im thinking fuel filter now

 

Just curious how that happened? I didn't think you had to oil the spectre filters? A non-oiled filter shouldn't be able to damage the MAF.

I hate to say it, but this has NOTHING to do with the new filter. Even completely removing the restriction of the stock airbox and running with no filter at all won't make a drastic difference in your LTFT's- especially not running it to -12. I'd agree that something else is definitely wrong.

Also, having a -12 fuel trim means that the PCM is pulling fuel, not adding it. If the MAF was reading so much more air due to the new filter, it would be adding fuel by means of a positive fuel trim, not taking it away. Negative fuel trims mean its seeing the engine is running too rich- and having the fuel trims that far off a near stock engine makes me think that there is a mechanical problem somewhere (O2 sensor not giving the correct info, MAF sensor giving incorrect info, fuel injector leaking fuel when closed, etc).

Lots of people have installed high flow air filters- and I can say for a fact, that the car getting stuck at 4000 rpm is not normal- something is wrong somewhere.

I believe 30 minutes without battery power should reset everything, but if you haven't fixed the issue, you're still going to have problems.

I don't think it could be a plugged fuel filter. Think about it for a second, the pcm is pulling fuel because it is running too rich. If the fuel filter was plugged, causing loss of fuel flow, and lower fuel pressure- the pcm would have to add fuel (positive fuel trims) to fix the problem.

 

it sounds like your car is in limp mode due to some thing wrong some where down on the line. the best thing is have some one that has a gm thech tool scaner and have it checked out. you can replace alot of parts with out having a scan done. bumpin is right about the timing and every thing about the 3800 motor. i would just check the computer out is should pop up with some thing with one or more sensors not working right.