Well, my wife has been driving our 'new to us' '99 SLE (it has 112,000 miles) for roughly 2 weeks. Yesterday she said she was stopped at a light and when she began to accelerate the car 'jerked a little'. That's all she was able to tell me. Yesterday I looked over the car and I didn't find anything wrong. There were no error codes. I took it for a 10-minute test drive, and everything behaved normally.

Today we were stopped at the SAME intersection where my wife said the problem occurred yesterday (what are the chances of that!!!), and as I accelerated gently in 1st gear the engine stumbled once and stalled. The engine light never came on. I put the transmission in neutral and cranked the engine. It cranked but wouldn't stay running. I probably cranked it 3 different times in neutral. The ABS light was the only light that was on. I put it in Park and cranked the starter again, and it started and I drove us home (roughly 1 mile).

I checked for error codes again after we got home today, and there were none. I looked under the hood and didn't see anything wrong. I even lifted the driver side carpet to see if maybe the ground bus was wet/corroded, but the floor was dry and everything under the carpet looked brand new, and the wires were perfectly taped so I didn't remove the black electrical tape to look at the ground bus.

I took the car for a 20-minute test drive today, and everything was fine; it didn't jerk or stall and there were no other odd behaviors at all.

Any ideas? I'm wondering if maybe this is an early crank sensor problem.

Thanks.

Anyone?

I'm wondering if maybe this is an early crank sensor problem? Or maybe a heat related problem with the ignition control module? Or maybe I messed something up when I replaced the intake manifold with the new redesigned one (GM Sure Fix manifold kit) that has the metal sleeve around the EGR passage?
History: The dealer replaced the lower intake gaskets with the aluminum ones while the previous owner owned this car, but the upper intake manifold had a '99 date code on it, so I replaced the manifold and also replaced the alternator with abrand new one before my wife started driving this car, to eliminate potential problems down the road. Everything went smoothly, and there have been no signs of leaks or anything. As I noted in another topic post, however, the new alternator makes the same high pitched noise that the previous alternator made.

Today just for kicks I also checked to make sure that the nylon EGR tube inside the intake manifold hadn't fallen inside or something; it was still in the correct position.
Any ideas?

Thanks.

Have you checked the ground under the ICM and the battery cables for corrosion?

I'll check the ICM ground and the battery cables tonight after work.

The ground and the battery cabled looked ok.
Rather than waiting for it to stall again with my wife and kids in the car, I bought a harmonic balancer and crank sensor from AutoZone today and had a local shop install them. I'm glad they pulled the balancer instead of me; they said it didn't want to come off. Took them about an hour and 15 minutes, and they charged me $70 for labor to replace the balancer and the sensor.

When I got the car home, there was a puddle of oil on the driveway; the front seal was now leaking. I took the car right back to the shop and they showed me that the seal looked fine but started leaking for some reason; the leaking seal material was orange. I bought a new Fram seal kit from Kragen (the seal material was brown) and they installed the new seal and put everything back together without charging me anything else. That made my day.

Now we'll wait and see if the engine stalls again...hopefully, it won't, but time will tell.

maybe check for corrsion or lack of good ground between the ICM and ICM mounting bracket apply silacone. have icm checked at a auto parts store if they do that there

Well, if anyone's been wondering what has happened since this problem first occurred, I had the crank position sensor replaced almost 3 weeks ago, and there hasn't been a problem since that time so it looks like that was the cause.