MarcR94v6

So 1/4 of a tank after I used "garunteed to pass emissions test" in my gas tank, as instructed by a smog technition, the car would die immediately after I started it. It couldn't idle, basically. I just replaced the IAC valve motor, got all new wiring and pigtails for the IAC IAP sensors and the other wire that goes into the throttle body. Those would have been my first guess If I hadn't just replaced them.

Today, my brother started it up, and revved it for a while, then kept it up at a certain RPM. After a while it idled on it's own. I had already tried this before the morning it happened, but not for as long as my brother did it. After he turned it off, it started right back up again the first, and the second try.

So what else could it be? Could it be that the slow working stuff I put in my gas tank ("guaranteed to pass...") is getting carbon all built up messing with my idle? The reason I think that is because sometimes I've seen people Seafoam their cars, and they had to do exactly what my brother did to keep it idling on its own because of the all carbon build up? Before I fixed all the IAC stuff it would die at stop lights, or whenever I came to a stop, I don't want that to happen again. Tomorrow, I'll take a look at the IAC valve and see how dirty it is.

What do you think?

StephenDeli22

Run a can of seafoam through to get all that carbon out. I dont think that much carbon shoult be in your IAC though. My intake system is clean as it can be. Could be a bad PCV spitting oil into your throttle body?

Also by looking at your car in the sig it should pass. Basically as long as your car has a cat and stock cam, ect. you should be ok. Did you try a tune-up?

MarcR94v6

No, I haven't, maybe I should get new plugs.

I just checked the IAC, clean as a whistle.

havoc06432

a couple things. Did you reset your cars idle after doing your mods? Did you reset your idle after the been last time the battery was disconnected? you might want to try the idle learn procedure even after putting all those additives in the car. After you've done that you can start doing other things to rule out the problem.