IowaClass65

I have a '92 Vert with 52,000 miles. She has been rock solid until recently. I noticed a slightly rough idle and a little sluggishness for about a month, Recently the engine has cut out for just a second several times. Once at start up but usually upon acceleration.and only when warm. The car always has started instantly, but I also have noticed it takes just a bit longer to start when this problem is about to happen. When this happens it is as if I hit a kill switch, just a quick, abrupt shut down for about a half second and then the engine starts back up by itself. Always when warm and usually after I park it hot and restart it 1-2 hours later. It throws an CEL when it does this, but I cannot locate an OBD-1 scan tool. The CEL resets itself after the car sits overnight. If anyone has a suggestion for a starting point, I would appreciate some suggestions. I am assuming ignition or computer. The previous owner said the Opti was replaced, but had no proof of this. TIA! .

vader86

The CEL code is still stored in memory, you must pull that code to make progress. No point in throwing parts at it until you know what the code says.

Autozone sells OBD1 code readers, as do most parts stores. They may have a guy who will pull that code for you.

IowaClass65

Okay, I finally got the car out for the season, and this problem cropped up the first time I drove it after sitting with the engine warm. I had the car parked about 90 minutes after getting it up to full temperature. One I started it again, I was merging on to the highway and the engine cut out. The tach immediately dropped to zero and after about a second, the engine came back and it ran normally until I got home. It did not reoccur and did some spirited driving. When this happens, it is like I turned the ignition key off. It immediately sets the CEL light.
I purchased the OBD1 reader and the code it threw is '36'. With the abrupt loss and return of power it seems more like an ignition problem than a MAF problem. The loss of engine is abrupt and total, but it is also very brief, lasting only a second or two. It starts well and runs well when not cutting out. This has never happened with the car engine cold. Any thoughts on where to start would be greatly appreciated!

Tom400CFI

The tach tells the story. Good observation there! The opti is dropping out. PO MAY have changed it...but buying new ones is a crap shoot. Thus, it could be new...but that doesn't mean anything, reliability wise. If your tach goes to 0 while the engine is still turning, you've lost signal from the opti....either b/c of the opti or the harness.

The Code 36 is for the opti too...adding to the "evidence". You likely need another opti.

stew86MCSS396

When you find the MAF sensor on your '92, please report back...

Sorry couldn't resist...

syco_cop

This is it 99%. I also have a low mileage msd opti from my 92 if your interested. Shoot a Pm if you are.

IowaClass65

Thanks, Tom. I suspected that this was the problem, although I was hoping that it would be something easier and cheaper. I am definitely leaning toward getting in queue for a Petris Opti, as they are having supply chain issues, like many. I will also replace the harness ($60) and then the decisions start. The car only has 52k on the clock, but I will still likely replace the 30 year old water pump and check for oil leaks. I also have new wires and Bosch fuel injectors which I grabbed just as they became scarce a couple years ago, since I am still running the originals. Thanks again!