93 3.1 v6 stalls, stumbles, dies

usually at coasting/stops. It starts up just peachy. seems to be an idle issue? The SES light would come on when dying but go off upon restarting. It has fairly new:
* O2 sensor
* plugs/wires
* oil & filter & air filter
* air charg temp sensor responds to temps
* idle air control valve reads 60 ohms (within accepted range)
* tcc solenoid unplugged

The engine doesn't knock, timing sounds spot on, and it has terrific power past 2000 rpms and is great on the highway.

I cleaned the IAC (not a good idea) and it *had* a few issues on hills and died more often. But I think it recalibrated because the problems lessened.

I got a computer readout and the codes are:
42 Electronic Spark Timing monitor error (Ignition Control)
35 Idle speed error (IAC)


However, after that I put some silicone around the aluminum side of some air intake houses on the throttle body. The ones *right next to* the IAC. In neutral I revved the engine whenever I had to come to a red light/stop, and when I got home it lasted, with no accelerating, 3 minutes at a stop- in Drive, Neutral and Park. It finally died in Park but maybe it was just getting hot, I heard the fan come on.

I don't have the funds to just randomly replace things until it's fixed (who does?). So, is there anyone out there that's had a similar problem with a simple/effective answer?

I replaced the crankshaft position sensor and so far so good. It seems to idle ok, it drives at low & high speeds just fine. It occasionally backfires so if anyone has some ideas in making it run smooth all the time...

[edited] um it test drove fine. It doesn't backfire or sound crappy anymore, but it still stalls & dies at low/coasting speeds, regardless of the previous speed it was at. I think it's the idle air control valve. I need a light at the end of the tunnel. Someone give me some feedback.

oh btw the auto parts guy said that the cps sensor can be ok but the thing on the crankshaft can get messed up. You can troubleshoot that by testing a new cps inside the engine w/ an oscilloscope. Or you could randomly replace things until you finally eliminate it by default.

on my 92 3.1 v6 i have the same prob with it stallin at low speeds. there is a sensor on the air intake that regulates the air flow. i took that out and adjusted it and now it is fine. if you take it off it has a knob on the end of a spring if you measure from the bottom of the spring to the end of the sensor it should be at 5/8 of an inch. no more no less. let me know if i can help any further

you mean the idle air control valve? I've tried 3 of em. I think it's fine, but I'll check again.

Last time I changed the spark plugs I noticed one was hardly used. I changed em again the other day- same story. So I pulled a sp wire, stuck a plug in it and started the car up. I wanted to see if I could see any spark. Very silly. It's easier to hear (or feel!*) the spark. My results:

1. unpug the middle sp it runs *like usual*
2. test some others and i lose some power/runs rough
3. test the middle one again, i lose power/runs rough.
I don't get it. Shouldn't it be rather consistent?

* the jolt wasn't that bad. I got worse from my dentist (grazed a nerve w/ a needle). Actually, shouldn't it be a pretty big shock?

I've got a spare ignition coilpack & module, I guess I'll just replace the thing.

i would start by replacing the coil pack. if it still doesnt work check the wire that runs to that plug it may be defective... also check the throttle it may need to be tightened. if it is loose it will idle really low and sumtimes stall. if you have any more questions or new iformation let me know. i am in the process of rebuilding a corsica for street racing and im sure i can help in many fields. email me at superskin88@myself.com

good advice! For those stuck in the same or similar position, here's the story:

Car stumbles, stalls, occasionally backfires, but mostly just dies. Happens at low speeds, either just starting (so NOT a tcc prob), or coasting/coming to a stop.

side note: if you slow down/stop *From* a highway speed and your automatic car stubbornly dies in driving gears, until cooled, it's probably the tcc solenoid.

Anyways, car starts up immediately and is driveable. Runs fine at high speeds. Can drive if you slip it into N as you coast to stops, go around slow corners, whatever. AS long as you don't hit 700ish RPMs or less you're ok.

So you run codes and only get IAC valve & EST.

I thought a bad IAC valve would throw off the idle, thus causing an EST issue. So I cleaned the IAC with no change in driveability :(

Now I start checking systems:
* air- vacuum hoses etc. ok
* fuel- pump & filter ok
* spark- seems ok
* timing parts- engine coolant temp sensor & crankshaft position sensor ok (camshaft sensor works because the car starts)

so wtf isn't working? last things to check are the ignition coils and ignition control module. Well, it fires at high speeds. Then why the dying??

The ignition control module has a high & low speed mode. The circuit for low speed (approx. 600 rpm & less) got the crap banged out of it because someone tightened the coil down too much. It fractured the plastic and worked itself off of the bolt. After driving for a long time the ign ctrl module couldn't take it no more & the low speed circuit bit it.

At least, I hope I fixed the problem! I'm getting the old part tested just for peace of mind. If it turns out to be fine I'll post again.