ive done alot of searching, and tried pretty much everthing. idk what it could be. the car was smokng white and the idle would be normal for a bit then stumble, almost die. so i went ahead and rebuilt the top end so i can pass smog, new head and HG and what have you. now the smoking is gone, but stumble is still there. there are no cel's

things ive done:
replaced dist with msd, and msd wire, plugs also replaced.
Timed really dead on(imo , after several dam times)
fuel filter is new,
cat converter has 30k on it
new o2 sensors
ran injector cleaner and sea foam, ive been thru a few tanks of gas to from diff stations.
ive adjusted the acc belt tension to make sure i wasnt puttuing to much drag on it.
map and IAC i know is good
compression is 195 across

so now when i go to a light, it idles good, then slowly goes down , then stumbles, some times goin up to lke 1k real quick and almst dyiing. vac is -16
could it be my throttle cable position? ECU?


96 atx
mods: dc header 4-2-1, cat back, cai, UDP, 55mm tb.
i have an exhaust leak right after the cat, (where cat and catbak meet) its kinda small, but will that mess up idle?

The exhaust leak shouldnt affect idle,

How do you know the iac is good? did you check it?

i have 2 420a's, it works fine on the other and its new..

sounds like an exhaust leak to me too