car has been acting up. meaning my car would idle weird high and low

[AK-49GSX]

alright so heres whats going on. for awhile now my car has been acting up. meaning my car would idle weird high and low and even start to surge when it warmed up. and even sometimes my car couldnt even hold an idle. that was the main issue. everytime i fired up it couldnt hold an idle. it would just completely die. now iv replaced my MAF sensor. my ISC sensor. got new spark plugs (gapped correctly) and as soon as i replaced my ISC which was today it fired up good and held the idle. the idle was a little high so i turned the scew down a bit so my idle was at about 850-950 RPM"S. so i turned off the car for about ten minutes and was happy and about to go on a test drive and fired up my car again and i noticed my rpms dropping to about 500 when i was backing up and then boom. it died. and now wont start again at all. idk what else it could be. im out of idea's. any suggestions?

ps. checked my BISS screw, ISC, MAF, spark plugs, and for any leaks.

 

[the_mork]

and for any leaks.

Do you mean fluid leaks or did you actually do a boost leak test? If you didn't then I would suggest that a boost leak test is the place to start.

 

[r6speed]

You mentioned you turned the idle screw down after changing the ISC maybe you did that when the car was cold and then the car went to warm idle which brought it down...is it holding steady at 500? If it is try adjusting it back up and see if it holds at 800 when its warmed up...I'm no pro just a thought

 

[AK-49GSX]

do you think a boost leak would make it not start at all? but no, the car doesn't idle at all. it starts up and just dies right away. it cant even hold an idle for more then a second.

 

[98gsxtuner]

Does is spit or sputter,when your starting it.

 

[AK-49GSX]

nope, starts up at normal and just dies. the only way keeping it alive is when i put my foot on the gas. and i just went and took it for a test drive and it drives perfect and no CEL came on. its just when i shift into neutral it dies right away. and it feels like i have all my power so i dont think its any kind of vaccum or boost leak.

 

[the_mork]

Doesn't matter what you feel in your butt, do a boost leak test.

 

[rEclipserGST]

Check timing and plug wires, maybe even your plugs... they could be fouled out. Also, do the boost leak anyway and check your vacuum lines. A combo of things could lead to instant stalling or no start. Search no start, and check those. Spark, Fuel, and Compression.

 

[boostingsx98]

its probebly your (TPS) throttle position sensor. I had the exact same problem and after i replaced it, it started up great and idled perfect!

 

[clean96GST]

sounds like the same exact thing my car is doing, I already went through the vfaq and still found nothing. I turned my idle up so it doesn't die, but it will idle around 1500 sometimes.