Thanks Tim I needed a change and something funny!! Keep at it puck, you'll get it figured out.

 

I don't have internet at home, so I have to use my office 5 min away. I'm leaving the computer for the night, but hopefully someone will respond by morning.

I unplugged the IAC with the engine running and nothing changed....what could this mean or not mean?

 

oh yeah, IAC resistances and voltages checked out ok on a previous check.

 

plennum gasket?

 

I guess I could add that when i start the engine, it stays at 1000rpm and creeps up to 1500rpm after 1-2 min. It seems to like hanging out at 1300rpm after that.

Seems to me that if it was a physical block, like butterfly obstruction, or maybe IAC obstruction, or maybe a gasket leak, that it would be what it is as soon as the engine starts up, and not "warm up." Thoughts?

Ok, I'm really going this time....my wife wants to go to this thing and I'm already in trouble for spending too much time on the truck today......

 

Code 21 came on because the engine was not at operating temp when you did the test. Warm up the engine good before scanning for codes.

If the IAC voltages check out ok, but nothing changes when you unplug it, its probably a big vacuum leak or bad TPS...but like you said, a vacuum leak would always show.

Try unpluggin the TPS and then start the truck.

 

The truck was warm when I got the 21 and I got it on multiple tests. I just had the TPS replaced. I'll try though.

I checked the throttle cable and cruise cable. All looks in order.
The throttle stop is resting agianst the screw, which is bout 3/4 towards the throtlle. It looks marled on the other end pretty good. Looks like the previous owner might have had some idle issues also....
The EGR and IAC are not leaking where they contact the throttle body.
I haven't checked the timing or ACT.

I got a check engine light on my way home last night. I was actaully thankful, maybe it will yeild an answer. The code pulled was a 41 for 02 sensor. I cleared it and drove to an event about 20 miles away and back. Haven't had a repeat occurance.

That's still where I'm at.

It might help to add that I get some hesitation when pushing the gas peddle. Then it springs to life and sounds great. It is hard to drive a stick when the hesitation occurs as you let the clutch out between gears...

I might try just replacing the IAC...according to some posts that is eventually unavoidable. I'll also look at the timing I guess.

Any idea where that screw should be? I know you aren't supposed to adjust idle with it, but it looks like someone has and if anything I'd like to move it back to where it originally was. One less variable for the computer.

 

Oh yeah. I had the TPS replaced by my local shop because I didn't know how to get the mounting screws out......newb.... Until Monday morning when I call them, I'll have to assume that it was properly adjusted when it was installed. I had this problem before and after the TPS install though.

 

Hmm, that screw would certainly cause your problems...High idle, code 13.

If i remember right, the screw had red paint on it. It should only be screwed to that point. I dont have my truck right now, so I can check.
Why dont you try loosening the screw while the truck is idling? It could bring it back to normal.

 

I unplugged the TPS after it was running. Got a slight idle increase and a check engine light.

 

Ok, so I backed that throttle stop screw back to where it is more like 50/50 in the plate and idle returned to normal. It is fluctuating between 500 and 700. Also, the volt meter drops to about 12 whenever it idles and acts like it wants to die. It did die when I tried a KOER test during the steering wheel turn part. I ran it again and now I'm consistantly getting code 12 and code 13...rpm high and low out of range.

I bit the bullet and got a new IAC. No change.

The hesitation is even stronger now. It stutters between shifts...particularly after 1st and 2nd.

I'm trying timing now (now that idle is back down). I have never timed this kind of vehicle before. I'm following the Haynes instructions. I hooked up my timing gun to the passenger front (1st) spark plug wire. On the distributor wiring there is a harness with several (5-7) wires and one off to the side near there that is jumpered to itself. I guess that is the SPOUT...I removed the jumper. The engine is warm so I tried the timing. The metal mark and the white line are lining up at the 20 degree mark. It isays to reference the emissions sticker under the hood for correct numbers, but I don't seem to have the sticker anywhere. I'm going to forum search more. Any more thoughts while I do so will be appreciated. The computer still cannot make the idle do what it wants to do.

 

ok, looks like the base is supposed to be 10?? I'll try it and see what happens...I can always put it back where it is...

Where is this bolt on the distributor I need to loosen to turn it? Is it the big nut I see under the big electrical plug that looks like the nut for the EGR exhaust hook up? My car is an RX-7 with the rotary engine and a different iginition set up, so this is my first experience with a regular V8.

 

Ok, I found the right bolt. It was already loose and I could turn the distributor freely.........I adjusted it so the saw mark is at the 10*, but the white line I see on the turning pulley doens't match up. It only matches up if I have it one the 20*.

Also, on the wiring harness for the distributor, there is the big one plugged into the disributor, the SPOUT, and a little further up is a black harness with a black wire and a black wire/yellow stripe. It isn't plugged into anything. I don't know what this is. There doesn't seem to be anywhere it should be plugged in.

I'm still running like crap and have no power. I don't see how I could pull anything. It is that way with both tanks, I have a new fuel filter, and the FPR looks shiny and new. My mechanic has a 91 F150 so I guess I'll put it in his hands tomorrow.

I'll take any more comment till then.

 

Cycle the key to RUN a couple of times. Now, go check the FPR. Remove the vacuum line that is on it and look for any signs of gas. If any, replace FPR.

Yes, base timing is 10*.

One last thing to check is your O2 sensor. A quick way to see if its working is to run a KOER test, but have the O2 sensor hangin outside the exhaust pipe. This will force it to read LEAN (real lean) and set off Code 41.

 

Ok, so my mechanic correctly adjusted the timing and used the screw stop to put the idle at 800rpm. I told him the computer should be adjusting the idle with out him moving the screw. He said it isn't happening that way. But, everything is running fine. Got the power back, sounds good, etc. He also said puttnig seafoam in the gas tank would help. I had been using TECHRON.

I went home and pulled codes. Still getting a code 12. This morning I drove it to work and the idle didn't kick up to warm up. It stumbled for about 30 sec as I idled in the driveway. I guess the computer still can't control idle. I don't know what to do about it. I guess I'll research code 12 threads.