Removal of IAC

[LithiumCobalt]

My mistake, I was thinking of the throttle position sensor, which the original poster has shown a picture of. The IAC is located on the driver side and can be replaced in 5 minutes without fanfare.

[AmuletOfNight]

I cannot find the IAC anywhere. Even the shop manual points it out to be right next to the TPS

[miamibob]

On my Dad's '93 GM it was lower on the intake on the driver's side. It's low so you have to look for it but if you use the above photos as a guide you WILL find it!

[VicCrownVic]

My guess would be, relative to the picture of the TPS you posted, that the IAC will be to the right of the TPS. As miamibob said, it looks like it may be a little lower than the TPS and possibly hidden or at least obscured from view.

[AmuletOfNight]

I'm afraid that is not the case. I search high and low next to that position sensor. If it's there, it's covered by something that would make it inaccessible anyways. Looks like a black piece of plastic right beneath the TPS blocks the view.

[miamibob]

It's NOT right near the TPS (IIRC). Look to the right of it and down. WAY down!

[AmuletOfNight]

No can do. There's enough solid material in the way to where it seems it would require a lot more disassembly than I'm willing to do. If it's not the engine itself being in the way, it's thick wiring harnesses, and if it's not that it's more engine. I have a feeling I'm just going to leave it alone.

[AmuletOfNight]

I've already been through a lot because I thought the TPS was the IAC. I removed the airbox from the intake and then found out that the rubber piece that goes on the snorkel for airbox didn't come with it, so I had to wrestle that back on, and in the meantime I found out that the rubber piece had a tack in it, making me slice myself. And also in the process of removing the bolt that secures the airbox, I sliced myself on a socket that had somehow peeled away and had a sharp sliver of metal (they just don't make Craftsman like they used to...) that will slice you if you touch the socket to pull it off (giant gash in my hand, now). And then I put the airbox back on after I found out that looking into the intake would do me no good, but the hose clamp came apart on me, so I spent 20 minutes trying to get the hose clamp back together around the intake!

And let's not forget that once all that was done, I started it up, and it stalled immediately. Started again, SHAKE SHAKE SHAKE SHAKE SHAKE ROUGH IDLE ALERT OH JESUS. And then the car stopped shaking and the idle went really really high, almost as if I was accelerating. I tried to give it a bit of throttle to quiet it down...stall. Started it again, stall. Again, stall. AGAIN, no stall, rough idle, shake shake shake, stall. Started it one last time, quickly put it in drive and gave it gas, no response and then it LURCHES forward. Stall. I was pretty sure I broke something at this point. I actually got it out on the road, gave it full throttle, it stumbled very hard before accelerating normally, but the moment I gave it anything but full throttle, it tried to die. Also full throttle seemed very weak. I got it back in the driveway, went over everything again, disassembled everything and put it back together. Started the engine "CHECK ENGINE" came on, car idled fine. Put it in drive, gave it gas, no response for .5-1 second and then it lurched forward and died. Well...at this point I was sure there was something very very wrong. Popped the hood and realized that I forgot to attach two vacuum hoses to the airbox. Put those back on and the CHECK ENGINE light went out, but the car still stumbled and stalled.

Just for the heck of it I looked one more time, and it turns out that I forgot to tighten a SINGLE hose clamp on the outside of the airbox. Was probably making a very bad leak of fresh air that the MAF couldn't compensate for. Upon tightening said hose clamp, all engine problems went away.

Always tighten your hose clamps.

[miamibob]

Sometimes it is good to step away from a car to collect your thoughts (or heal up your cuts!). Is the MAF sensor clean? You would need the special MAP Sensor Cleaner (CRC makes one). There are special security torx screws (T20's IIRC) but the are not the regular torx screws - they are the security versions (not a hole in the middle but a "shaft"). If you do this DO NOT make any contact with the wires on the underneath of the sensor. Spray them thoroughly and let dry completely before putting the sensor back in. By the way, the IAC is down there but may be hidden, somewhat by wires and/or that black plate by the intake. Continue looking for it using the photos as a guide. It IS there.

[AmuletOfNight]

I have cleaned both the IAT and MAF that go into the airbox. I cleaned the MAF quite a while ago. I remember because I had to go buy a set of security torx bits to get it out. I cleaned it just like you said. Shortly after that I found the IAT and cleaned that as well, but the cold stutter never went away. Maybe I should clean the MAF again?

[miamibob]

Are you using a standard air filter or something like K&N? I ask because any of those "special air filters" use oils that wind up coating the MAP sensor. Cleaning it again shouldn't hurt but may not fix the issue. Probably still the IAC.

[AmuletOfNight]

I'm using a standard FRAM air filter, no oil or special coatings like that. Although, the last air filter I pulled out of it was FILTHY. Maybe it re-coated the MAF with dirt and debris. But I'm also still wondering about the IAC. Because my idle goes up and comes down fine when it first starts up. Wouldn't that eliminate the IAC?

[miamibob]

IAC issues can come in various forms but the typical one is stalling at idle (especially nice at red lights and STOP signs)!

[AmuletOfNight]

Well, that is not an issue for me. Idles fine at red lights and stop signs. I'm not saying it's not the IAC, but the typical symptoms don't appear to be there.