Rolling IDLE Fine, Stop any Forward Motion, Idle Drops to 500

[SpazmSi]

Here's what I have done,

1. Searched 2. Cleaned IACV3. New MAF4. NEW TPS5. Adjusted and Re-Adjusted TPS and Idle

Car was good for a few days, but doesn't handle temperature changes well, Runs fine on cold (dense) days, lopes and drops idle on hot days.

Thing is, while rolling at any speed, the car idles at about 1200, I can push the clutch in, let the engine drop to idle and come to about 1mph with no problems, but the instant my wheels stop rolling, Idle switches/drops to 500 and lopes up and down, 200 rpms.

[mrzabala]

Check your vacuum lines. If you suspect leaks, get a tub of water and remove a vacuum line and drown it couple inches at a time to search for bubbles. Replace as needed and make sure you tighten or have a good snap clip holding the vacuum lines..

[vancouverbc]

Did you take plastic piston and spring out of iacv and clean? cleaning throttle is the first thing to do. disconnect aiv hose going to filter box.

[mrzabala]

Well doing it my way is much easier, and it will more likely be the cause. IACV will usually outlast vacuum lines or many other parts on a car. Also, theres little effect or no effect if your cleaning the throttle body. Rather, check if theres leaking inside or outside since coolant passes through it, check if the plate opens and closes correctly by manually turning the throttle pully. It should open half way at fully depressed and closed with little to no air leak.

[jdm_master_X]

well remember when he is accelerating his idle is dropping. during decelleration that is when your vacuum is the highest. its kind of difficult to guestimate the problem if it only occurs during acceleration.

if you apply any sort of throttle to the engine, what happens to idle?

[vancouverbc]

well remember when he is accelerating his idle is dropping. during decelleration that is when your vacuum is the highest. its kind of difficult to guestimate the problem if it only occurs during acceleration.

if you apply any sort of throttle to the engine, what happens to idle?

His problem is occurring during deceleration. I have disconnected vacuum hoses and it only raised idle by 100 rpm.

[SpazmSi]

Well I have checked for vac leaks using the ols' carb cleaner method, I didn't disassemble the IACV to clean it, just removed it sprayed cleaner in every hole and adjusted the screw in and out a few times.

My problem isn't really while decelerating, or accelerating. I can let the car drop to ILDE while rolling and it holds at about 1000-1200 RPM, but as soon as I stop moving forward, the idle drops sharly and will not hold steady. My car is a 90 180k+ miles so there are surely many things wrong. I will be doing a lot of maintenance soon, timing chain, gaskets, distributor etc etc.

I was just wondering if there was some input I didn't know about.

[vancouverbc]

The IACV is probably causing the symptoms you describe. worth cleaning.ONCE you take epoxy off you can adjust spring. i can get my car to stall at stop signs by adjusting spring. it has dramatic effect on idle.