1999 Olds 88 cuts out momentarily. No MIL. Otherwise runs well

I’ve never had a car act like this before. It cuts out for a tenth of a second, and then comes right back. I drove it 20 miles yesterday. It seemed to do it more before the engine reached operating temperature, like once every quarter mile. Once on the interstate, it went down to once a mile, then once in three miles, but it never completely quit doing it. I tried jiggling the keys in the switch. It made no difference. It did not make a difference whether or not I was going up or down hill or on level ground. I had the cruise set for 65, and it held that speed well. I’d think if it were a fuel filter or pump issue it would sputter constantly. This is just a sudden hiccup, then right back to running perfectly.

3.8 L V-6, 126K miles.

Any ideas what’s going on?

My best guess…and it’s just a guess would be the Ignition Control Module. They can do some crazy things when they start to go bad. Have you checked for loose connections on the ignition coil?

Update… I just spoke to a friend of mine who is a mechanic and he said that your description is a common sign of bad gas. Gas runs the engine…water won’t.

I put five gallons of fresh gas in before my 20 mile trip home last evening. The bad gas theory might account for its improvement as I drove. I know the car sat for a while before I got it, but i don’t know how long. This AM the MIL came on during my trip to church. I’ll hit O’Reilly’s on the way home and post the results.

Bad Ignition Control Module and or wires.

Or a bad crankshaft position sensor.



The scan code is P0102 “Mass air flow circuit, low input”. WWW. enginecodes.com (which popped up on a Google search for OBD II P0102, but is now among my bookmarks) says replace the air filter which appears quite clean. Then CLEAN the MAS with low pressure air or MAS cleaner. Only replace the MAS if the above doesn’t cure it. I have MAS cleaner at my shop, but not here at home today.

Can the MAS cause the intermittent hiccup I have, or is P0102 a second issue I didn’t know I had?

A leak in the snorkel can also give a maf fault. Maf fault changes the air to fuel ratio causing poor running.

Water in gas or an intermittent ignition problem of some kind is my guess. I think the MAF code is a red herring, you may have a problematic MAF, but it is unrelated to the symptom. If it is water in gas, it will go from worse to better as the water gets used up, since the water will go to the bottom of the tank, and get drained out first by the fuel pump.

I’ve wondered if gas with ethanol would disperse water by itself without the addition of a plastic bottle of “HEET” . Isn’t HEET just ethanol?

I’ve had something like that twice. Once was the crank sensor as tester said, but it was only on a hard acceleration until it finally broke off and left me on the road. The other time it was a bad plug wire.

I've wondered if gas with ethanol would disperse water by itself without the addition of a plastic bottle of "HEET" . Isn't HEET just ethanol?

Good point, I think it should. HEET is methanol.

@Bing I’d think a bad plug wire would show up as a miss on one cylinder with s P030X code. The crank sensor is a possibility as it’s more like all six cylinders shut down for an instant.

Probably but I never got a code on either one. Maybe because it was so slight and quick.

I can tell you guys, from experience, that not all bad plug wires results in a misfire fault code