need help... well i up my boost form 6 to 9psi still running a tadd rich so i'm not worried about blown engine... but my car recently started idling really rough. At initial start the car starts up then sputters and dies... after starting a few times the car stays on however it idles at 500Rpm and feels like it's going to die... what will cause this?

Bad MAF?
Plugs?
Bad O2 sensor?
not a boost leak i checked with boost leak tester..

Done my research... tried google... i'm pretty much all out of ideas...

 

i had the same issues recently and my problem was that my timing was off by a tooth...look and see if your timing marks are on point...my 2cents

 

Really Timing will make it sputter like that? hmmm... interesting.... i will have to look... good thing i have fidanza adjustable cam... the only weird thing is that when i drive the car it's completely fine... just when i start it it sputters... and or idles low/Rough... The car also needs a good tune up... hasn 't been into the dealership since i bought it in 03...

 

yea, mine would drive fine too and start up fine, but then as it sat and idle'd, the rpm's got lower and more rough, sometimes cut off....it cut off on me like 5 times while i was trying to back into my garage

 

Yah i would check your timing that would make a difference and also what is your cold start set at

 

well the car was running fine and all of the sudden it just started doing what its doing now... how do i check my cold start? would the dealership work on my car for the fact that it is modified?

 

Oh yeah! They'll be happy to take your money!

Warranty work may be another story...

 

haha that goes to show how bad I want to find the problem... grrrrrrrrrrrrrrrrrrrrrrrrrrrrr all great for two years and now it's blah....

 

I'd say do a tune up first if it hasn't been done in a while. Start off with the simple, cheaper stuff first. If you do your regular maintenance when your supposed to, then you would have an easier time trouble shooting your problem.

 

It is probably your ISCV.

 

I agree I would go through change plugs, fuel filter, air filter, etc. Just to be sure and can write those off as not the issue

 

Does adjusting your BISS make any difference? Does it act the same when the engine is cold started as it does at temp?

 

Don't mess with the BISS screw. It's one of those things that you never mess with unless it's leaking. Only time you would need to adjust it is "maybe" when you replace the throttle body or have to replace the BISS screw because it is leaking. Just like the old saying, "if it ain't broke, don't fix it".

 

Well without adjusting your BISS to see if your engine can be corrected from it's cold start idle, I'm leaning towards a bad IAC motor. Give your throttle body a good cleaning. Have you done the "coolant bypass" mod to your throttle body, by chance?

 

Once you have done your tune up stuff, if there's still a problem, I would say it's the egr valve or O2 sensor. Just my .O2 lol