94 SE, Idle problem, not stalling

Just bought a 94 SE, manual tranny. It cranks, it runs, but idles funny. When you crank the car you have to give it gas, and after it warms up a bit it will start the funny idle. It revs between 500 and 1500 rpms, just up and down, up and down, in perfect rhythem. When you drive it, it doesn't do it. When you push in the clutch it takes a second more than it should for the car to idle down, and then starts revving again between 500 and 1500 rpms. It doen't try to cut off, and it's not missing when accelerating or decelerating.
I read on a couple different boards that the IAC, EGR, TPS, and MAF can cause this. I just finished cleaning the EGR with carb cleaner, and am working on the IAC. I'm also replacing the battery. Going to clean the O2 sensors as well. I would see about the TPS, but I have no idea how to adjust or clean it.
Can anyone think of what this may be if what I'm doing doesn't work? Or can somepne please tell me how to adjust the TPS? I don't have much money to invest in replacing parts at the moment, but I want to be able to drive it. I also read something about resetting the computer when you work on the car, or replace anything. How do you do that?
If it helps any, the EGR I cleaned was the original one that came off the assembally line (will replace next week), and it looks like no one has ever touched the IAC.
Thanks for any help you may be able to give.

Hi there, I have had the exact same problem happen to me a year ago.. except I have the V6. After ALOT of searching it turned out to be the Idle Air Control Bypass Air Valve (or IAC BPA Valve). I had the same symptoms, first off my car would run ok at fast idle when the engine was cold.. but as soon as the car would warm up the idle would be inconsistent and fluctuate between 750-2000 rpm or so. What happens is that in the IAC BPA valve there is a valve made of a thermalwax material and it's affected by the coolant temperature (i.e. the reason the engine runs fine when cold) but when the engine warms up this valve is not working properly and causes a sporadic idle. Try replacing it with a used part from a junkyard.

G-Luck


Just bought a 94 SE, manual tranny. It cranks, it runs, but idles funny. When you crank the car you have to give it gas, and after it warms up a bit it will start the funny idle. It revs between 500 and 1500 rpms, just up and down, up and down, in perfect rhythem. When you drive it, it doesn't do it. When you push in the clutch it takes a second more than it should for the car to idle down, and then starts revving again between 500 and 1500 rpms. It doen't try to cut off, and it's not missing when accelerating or decelerating.
I read on a couple different boards that the IAC, EGR, TPS, and MAF can cause this. I just finished cleaning the EGR with carb cleaner, and am working on the IAC. I'm also replacing the battery. Going to clean the O2 sensors as well. I would see about the TPS, but I have no idea how to adjust or clean it.
Can anyone think of what this may be if what I'm doing doesn't work? Or can somepne please tell me how to adjust the TPS? I don't have much money to invest in replacing parts at the moment, but I want to be able to drive it. I also read something about resetting the computer when you work on the car, or replace anything. How do you do that?
If it helps any, the EGR I cleaned was the original one that came off the assembally line (will replace next week), and it looks like no one has ever touched the IAC.
Thanks for any help you may be able to give.

I looked in my Haynes manual for the IAC BPA and can't find a listing on it. Where is it located?
I just finished putting my car back together. Got the EGR, IAC, and Throttle body cleaned out. Replaced battery, PCV valve, and air filter. Car is still doing the same thing when it warms up, though I had to start driving it for it to act up.

Hi there, I have had the exact same problem happen to me a year ago.. except I have the V6. After ALOT of searching it turned out to be the Idle Air Control Bypass Air Valve (or IAC BPA Valve). I had the same symptoms, first off my car would run ok at fast idle when the engine was cold.. but as soon as the car would warm up the idle would be inconsistent and fluctuate between 750-2000 rpm or so. What happens is that in the IAC BPA valve there is a valve made of a thermalwax material and it's affected by the coolant temperature (i.e. the reason the engine runs fine when cold) but when the engine warms up this valve is not working properly and causes a sporadic idle. Try replacing it with a used part from a junkyard.

G-Luck

On the 2.0L the IAC BPA is located on the top of the throttle body. When I was having problems with my IAC BPA, I spoke to a mechanic at ford and he informed me that the IAC is NOT serviceable... so even if you had your throttle body cleaned.. it would not solve the problem

I looked in my Haynes manual for the IAC BPA and can't find a listing on it. Where is it located?
I just finished putting my car back together. Got the EGR, IAC, and Throttle body cleaned out. Replaced battery, PCV valve, and air filter. Car is still doing the same thing when it warms up, though I had to start driving it for it to act up.

Is that the piece that the IAC bolts onto? If it is, then I cleaned that too. I took apart the entire assembly on top of the throttle body. And man was it a pain to get off! Ended up replacing the screws with bolts after it took nearly an hour to get out one of the screws because you can't get to it.

On the 2.0L the IAC BPA is located on the top of the throttle body. When I was having problems with my IAC BPA, I spoke to a mechanic at ford and he informed me that the IAC is NOT serviceable... so even if you had your throttle body cleaned.. it would not solve the problem

The IAC BPA bolts on to the top of the throttle body. It doesn't matter if you cleaned it, it's a temperature operated thermalwax valve... if it's damaged or broken... cleaning it won't make a difference... Replacing it is the only way, try to get one from a junk yard.

Is that the piece that the IAC bolts onto? If it is, then I cleaned that too. I took apart the entire assembly on top of the throttle body. And man was it a pain to get off! Ended up replacing the screws with bolts after it took nearly an hour to get out one of the screws because you can't get to it.