i took off the throttle body and half assed cleaned it before i got the t20 security bit to remove it, ill remove it tommorrow and clean it(i bought MAF cleaner) directly. im really starting to think it may be the cam/crank sensor. just checked alldata, that looks like a pain to diagnose/fix, i aint gonna try it if thats it. lol
edit:somebody suggested that it was the idle air control valve. could that cause it? its happening at idle, and idleing lower.

The IAC controls how much air is coming into the engine with the throttle plate closed (foot off the gas pedal). If it is sticking you will definitely experience stumbling at idle. If the car is stumbling during acceleration, though, I would not suspect it because when the throttle plate opens the IAC is bypassed.
What type of air filter do you use?

i have an intense fenderwell intake, it came with a bigass k&n cone filter. i noticed today that there is definatly a "burnt charcoal" smell when/after it dies. and the hesitation is right at 1k rpms(where it idled at normally), it sticks there(on the tach, not the boost gauge ) then runs fine once it gets past it.

high flow cat. was this a brand new unit or used? did you install or shop?

do the SSEI'* require any kinda of PCM tuning when adding this mods?

brand new, exaust shop installed it. i checked it for leaks already. it shouldnt need tuning for the mods ive done. i know that briefly before(months ago) there was a code for EGR flow, could it just be a bad EGR valve?

it should be simple enough tto get to. at least on my SLE it looks to be. there again, i have heard of a tap method to see what happens at idle.;...tap the egr valve with a screwdriver handle or something...see what it does. otherwise, unbolt it and see how bad it looks as far as carbon build up. my guess is that it is probably plugged if you have signs of bad o2s there were nasty and with the coolant issue before....probably alot of nasty carbon buildup. also, could have a plugged egr tube too...so check both. free to remove and inspect!!

well, i just ordered my IAC, im gonna change that and probly my vac line(since it is damaged/repaired anyhow). then maybe take a look at my EGR. if that dont work, im taking it to a stealership(i know I keep saying that, but the IAC and vac line are easy to change).

IAC didnt work. it revved up to 2300 rpm, stayed there, then i turned it off then on again, and it went right back to fluctuating and dying when i drove. im still gonna replace the vac line, but after that im done guessing for sure.

put a new vacuum "harness" (as the dealership calls it) and its idling better, hasnt died yet. still has SES light on and it runs weird still. rpms still fluctuate, but it at least is closer to the regualr idle speed.

i think im having the same problem ill just have to check into that i thought it was the cat i just wasnt sure!