I've just replaced my cap, coil, rotor, wires, and plugs. I had put in an accel ignition module, but it caused alot of stumbling and just general hate and discontent with the rest of the ignition. I put the stock one back in. The car is fine until it gets up to operating temperature, then it sometimes stumbles a little bit. Sometimes more than a little. What might be causing this? I put dielectric grease between the distributor base and module. Now I'm kindof scratching my head saying WTF?

 

Is the "stumble" occurring at all RPMs or only on accelleration, just off idle (throttle tip-in), during decel, or at a particular time?

 

It will only occur when the engine is at operating temperature during acceleration until about 2,000 RPM. After that, it seldom studders. The idle quality is good.

Maybe I should tell a little more. I've been following a thread by fruity one about the computer throwing a code 36. Mine is doing the same thing, and like one of the guys in that thread, I replaced EVERYTHING in that circuit to try to get rid of it except the ECM. Still, code 36 remains.

I had an oil leak in the back of the manifold. I thought maybe the studder was from oil getting up into the distributor leads causing a poor spark. I replaced the manifold gaskets and got rid of that leak. The studder is still there.

While I had the plenum off, I removed and cleaned the IAC. I haven't had a chance to check the voltage on the TPS yet though. I was thinking that it could be causing my problem.

Today it ran the worst it ever did...almost like it was missing. I shut the car off and it ran better after sitting for about 10 minutes. Any help would be appreciated.

 

Just a bump looking for some help!

 

Ok, I tried removing the EGR vaccuum line, but the stumble was still there upon reaching operating temp. That's probably not it then. I put it back together.

I adjusted my TPS voltage, and it was only slightly off. The stumble was still there at temperature.

I put a new coolant temperature sensor on the connector, but didn't fully install it. The old sensor was still in the block, and the new one was reading the underhood temperature. NO change to the stumbling condition.

Timing is set at 8* advanced

Any ideas anyone?

Edit: If anyone has a helm's manual for an '89 IROC-Z L98 and could post the troubleshooting procedures for a code 36 I would really appreciate it!

Also, do you guys think I could run 12 volts directly to the MAF to do my own ghetto burn off, or would I fry something?

 

I'm going to replace the EGR valve and see if that's it. It's the only thing I can really think of. I'll let everyone know how it goes.

 

I'm going to replace the EGR valve and see if that's it. It's the only thing I can really think of. I'll let everyone know how it goes. Of course, I live in the furthest sticks of Wisconsin right now and if you want a damned set of windshield wipers they have to special order it!

 

I replaced the EGR, and it did help out, but there is still a stumble when the car is at operating temp. How can I test the EGR solenoid?

 

Any help would be appreciated guys...

I reset the base timing today, because I hadn't disconnected the EST wire the first time. In my chilton's it said to jump the A and B terminal of the ALDL. I disconnected the EST (tan wire black stripe) and set the base timing to 6*. When I reconnected the EST, the computer advanced the timing beyond the timing marks. The stumble is getting progressively worse, and I'm kindof at a loss. She'll now stumble while hot at almost any RPM or throttle position. I've heard the rotor clicking around in the cap at startup. Could that mean it's worn and wobbling inside the shaft? Unfortunately I don't have a laptop with WINALDL or access to a scanner. Really guys, I need your help here.

There is also a voltage drop when the car is hot. While it's cold it will read about 14V, but when it's hot the voltage may drop as low as 10V. I have just put in a new powermaster 140 amp alternator. Any ideas about that?

 

My car would "stumble" as if it were running lean or rich....much like a carbeurated engine would with similar symptons. My mechanic checked it out and told me that the injectors were bad electronically. He did a test with an DMM to check the integrity of the injectors. From what I recall, they should read between 11-14 ohms, nominal. The bad ones I had were reading 8ohms.

I had to replace all 8.

 

Well ladies and gents, it turns out I do have at least three leaking injectors, as well as a faulty ECM. The computer only flashed me a code 36, however a code 42 was there as well on the mech's computer.