Crank Position Sensor--'87 Century

I'm dealing with an '87 Century with a 3.8 engine.

This car has the chronic ocassional misfire, engine die in motion symptoms. A while back I replaced the crank position sensor, and all was well. Now the problem has returned. The symptoms are the same. The car has only 28,000 miles on the odometer, and the CPS has only 1500.

Can a crank position sensor fail after only 1500 miles? What's the likelihood?

I'm going to pull the cps this morning, and reseat it, ie: pull it out, look at it, maybe clean it, and put it back in. Its a fairly easy job. I'll put it back, if it looks okay, because a replacement, Borg Warner, costs $62.xx.

Does this sound like a plan?

Update. I pulled the crank position sensor and looked at it. Everything appeared good, other than a bit of dust. I took it to my local parts store (been dealing with them for 25 years) for their opinion. They have no way to test it, but said, "It certainly shouldn't have gone bad in 1500 miles. Here, try this one, even exchange." Their idea, not mine, to exchange it.

The new cps is in, and I'm not at all sure it's any better. I haven't driven the car yet, but it seems to stumble when I rev the engine, and drops below normal idle when I let up, before evening out. It died once just idling in the driveway.

I'll do a test drive as soon as I clean up a bit.

Why do you assume it is the cps, many other parts can cause this, the ICM, a bad harness form the cps to the icm, known bad ecms in those years. Try disconnecting the maf and see how it runs, another common area on those cars.

Why did I go with the cps? I guess because it is the most familiar, and the symptoms matched. I have had the ICM out and tested. It tested good.

Based on your suggestion, I read about the MAF in the Haynes book. When I tap it, engine idling, warm, the engine stumbles. When I tap it harder, the engine dies. It will restart right away. According to Haynes this indicates a bad MAF. When I unplug the electrics from the MAF, the engine continues to run, though a bit rough. When I disconnect the air intake on the engine side of the MAF, thereby giving the engine unmetered air and no MAF input, the engine will not run, it dies immediately.

Guess the MAF is the next replacement.

I replaced the MAF yesterday, and there seems to be a great improvement. :grinyes: The car ran as it is supposed to run.

It would be such a releif to have this car running well. I hope this solves the problem.

I always appreciate the help I receive here.