95 Bonnie Flat-line while driving
 

The last two days my bonnie has been acting up. It's a 95 SE with 180k. While driving down the road at highway speeds it will flatline for a split second and then run fine. Everything seems to die, engine, a/c, etc. It lasts for a split second and then everything is normal, without having to restart or anything. It happened in a parking lot once and I had to restart, but usually everything comes back on and the car continues to drive fine until the next event. I have a 15 mile commute and it happens 3-5 times per trip. Any ideas would be helpful. I've checked the ground center by the drivers door under the carpet and everything seem fine.
Thanks, Tom

Does the car loose all electrical power or does the engine simply cut out for a moment.

Sure sounds like a crank position sensor to me. I'd suggest checking the pcm connections, battery cable connections before going to the CKP but it's likely the CKP.

I believe it's the majority of the electrical system. It's so short that it's difficult to tell, however, I do hear the warning bell come on (same sound low fuel or low oil level), so that is definitely energized. The a/c blower definitely cuts out. Seems to be random warning lights coming on during the brief outage. I guess those lights come on when starting the car normally. Does that lead to the CKP? Can the CKP be checked or should I just replace it? Is the PCM under the seat or in the engine compartment? What's amazing is that there's no warning. In a blink the car is off and then back to normal. The 95 is the OBD transition, so it's impossible to find a scanner that they lend at the auto stores.
Thanks, Tom

the things I'm looking at won't show up on a scanner. Since it happens so frequently...let's do this..

Next time it happens.. notice if this is the scene.
dinger
car stalls
fan speed slows down considerably because it's on battery only and not alternator
power steering cuts out temporarily with the engine

If that's the case..it's most likely the crank sensor.

the car is basically stalling and restarting on it's own.

What you describe seems to be similar to what I experience. It happens so quick it's difficult to determine the order of the bell, warning lights, etc. I drove the car home today with no issue. Any special tools required to replace the crank position sensor? I may opt to replace it so I don't get left on the side of the road. Thanks, Tom

Only thing to keep in mind that isn't standard...would be the bolts to pull the balancer.

M6 x 1.00 x at least 75-80mm in length. GM gave our balancers the smallest bolts ever and usually you can't find them in puller kits.

I described my car as a hiccup. Happens quick...by the time you notice..it's recovered. Then your heart needs to recover from seeing the low oil light..lol

Hiccup is right on. This morning on the way to work it hiccuped at least ten times. Then on the way home - not at all!

As I've gotten older, I'm less inclined to do my own work - it's getting much more difficult to pry myself out from underneath the car. Anyway, I spent yesterday at three different auto stores getting the right crank sensor. I went to two different stores today looking for the flywheel tool but no luck. They used to sell those things everywhere, and now nobody has them?

Update: I picked up my car after having the crank sensor replace for $190. On the drive home the car hiccuped again and left me on the side of the road - killin' me! All power goes out while driving - clock resets, no lights, bells, no hazards, etc. After sitting for a few minutes it comes back to life. Anyway, ECM next? Thanks, Tom

Have you checked the alternator out put, the battery voltage while running and not? How about the battery cables..are they clean and free of corrosion?

Battery terminals seem clean. Today, when the car stalled, once I got it restarted, the alternator output was a right at the upper end of the red. Occasionally it would pop up to 13/14 volts and stay for a few minutes and then drop back down. As it sits at my house the battery is at 12.6 volts. Would a faulty pcm make this fluctuate or does this indicate a bad alternator? If I replace the PCM do the new ones come with the PROM or do I need to keep the old prom? Thanks, Tom