ok what's going on here

[Riley2.4L]

ok So my S14's gas mileage has been going to **** lately. Because of that and the fact I was blowin black gas smelling smoke out of my exhaust pipes I assumed the car was running really rich and I replaced the front O2 sensor ( only had money to buy the one at the time). Afterwards my gas mileage improved greatly but sometimes when I cold start the car it idles for a moment and then dies.

Also even before I replaced the O2 sensor the car would often die when ever I put my transmission (auto) into reverse. It sometimes dies while in drive unless I feed it hella gas. Anyone every experience this. Any idea as to what the problem(s) is.

[DjPantsSpecR]

i'm gonna have to say IACV. And there is a lotta misinformation going on around here, so i'm talking about the one on the intake manifold itself, not the PAIR valve

anywho, i can prove this because mine worked and started up just fine. When i plugged it, and i still have it plugged, it fired and then died. Thats what it does, thats what it always does. this usually only happens during cold start, but after little warm up it idles rock solid. However, prior too this it needs to be kicked a few times to keep it alive, especially depending on how cold it is

IACV, worst thing to ever happen to our KA

[Riley2.4L]

thanks for the info but help me out alittle bit I don't consider myself a noob but I'm definitely no expert. Whats a IACV?

Update: today while I was driving on the free way the car died on me. when I start it up it idles fine with some of the problems I spoke of before but when I put the transmission into drive or reverse it dies. Same problem or new problem?

[SimpleEnigma]

IACV = Idle Air Control Valve...a sneaky little bugger hidden in the depths of your intake mani. could just need adjustment, or cleaning.

When was the last time you checked your igniton system? I had a similar problem and it turned out that my distributor cap and rotor had disintegrated on me.

[Riley2.4L]

Its been forever since I last checked my ignition. the distributor cap and rotor theory sounds very likely though. I'm gonna check it today

[DjPantsSpecR]

yeah, i gotta agree because an IACV problem wont make your car die when its not idling, such as like you said on the freeway

[surfwax95]

Do the S14s have IACVs too?

My car idles very unsteadily (sits at 1000 then drops to ~250 rises back to 750 over and over)

[DjPantsSpecR]

yep, they definately do, i can at least verify they do on 95 and 96 motors. You almost have to pull the upper intake manifold to even touch it

[Riley2.4L]

ok UPDATE. finally went and replaced the distributor rotor. Now it doesn't die on me in idle or low revs. but the car still gives black smoke out of the tail pipe when the transmission is in first gear and engine is reved to 3k ir higher. any thoughts or is it time to take this KA out to a field and shoot it?