DTN

I drive a manual. When i got my car it smoothly transitioned from accelleration to decelleration. It kinda jerks now as soon as i let my foot off the gas. I'm wondering if this is a IAC issue, like it is somewhat clogged, or if it's something else. Curbside idle is 900. My idle ups above 1000 when I turn on my A/C, so i know it's working.

Another thing, I may just be immagining things, but it seems to be a bit better after a ECU reset. I've got no other issues, no codes, no drivability issues, it just wants to accel or decel even at 35 MPH in 3rd gear.

My question about the IAC is, Does the IAC actuate in steps, or is it fully open or fully closed? Also, what controls the ECU's decision to increase/decrease idle?

hamhead

I'm pretty sure it opens in steps, and fully closed is not all the way closed, so just in case it dies it doesn't kill the car.

Have you done any mods in the area (BBTB/Air-Ram)?

DTN

no. Everything on my intake after the CAI is stock.

Other then a Keifco.

REDZMAN

Your TPS is probably going. As for the IAC, you CAN clean it.

zoned019

I noticed this happen right after I did some performance mods (i/h/e, did them all at once). You have to have a smoother foot, otherwise the car jerks when you accelerate/decelerate. I just figured it was because the card had more pull, so it felt that way.

DTN

^^ well yeah, maybe that's why I'm noticing it more.



Thanks REDZMAN.. I didn't realize my IAC was not actuating correctly. You know how when you rev it drops to 2K, then 1.5K, then then Idle or something like that? Mine didn't have the 2K hold, it just dropped straight to 1.5, then idle. I had forgotten it was supposed to do that. I ran some Sea Foam Deep Creep through the IAC backwards, rather drenched the suxor, while i was spraying the rest of the engine for a 2nd shot of Sea Foam. It seems to idle down slower. I havn't done enough testing to figure out if the problem is gone yet.

That IS a function of the IAC right? Where does your engine hold? Does it have more then 2K, 1.5K, idle? Should i hit my IAC again?



Yep... fixed. thanks guys.

Vladimer

sort of ontopic / ot but,

when im in first, especially first and little bit on second, the car bucks like crazy, second just engine brakes so its fine there as far as i can see, but in first, you have to have a super crazy smooth foot, like if im not holding it at perfectly 3k+ rpm, even lifting my foot like a half a cm makes the whole car buck like a bronco. so im stuck letting in and out the clutch, pretty much riding it if i have to be in first,

now would this have anything to do with this IAC? its the first time i ever heard the term so not fully sure on what it is/does

DTN

found something



The idle speed control actuator is the double coil type and has two coils. The two coils are driven by separate driver stages in the ECM. Depending on the pulse duty factor, the equilibrium of the magnetic forces of the two coils will result in different angles of the motor. In parallel to the throttle valve, a bypass hose line is arranged, where the idle speed actuator is inserted in.

Circuit Diagram