Intermittenly, while driving at highway speeds and needing to accelerate slightly, the car acts as if the engine has been shut off, and the speed starts to drop. It'* happened about 4 times in the last month and a half, usually between 70-75 mph, although once at 65. It has never happened at in-town speeds. No lights come on on the dash to show that the engine has stopped, no check engine light, and all gauges appear normal. The boost gauge changes, and the rpms hold steady - almost as if frozen in place. Easing off on the pedal, and then stepping on it again gets things going and everything runs fine. It'* never happened while the engine was cold, always at operating temperature. It has ranged from engine running time from about 15 minutes, to an hour or two. There are no strange noises that are heard, and it doesn't sputter...just immediately acts as if the engine has stopped.

It was a lease vehicle that I bought used with about 47,000 miles on it and I've done several PM items. New plug wires (resistance measured when installed), new plugs (AC-Delco OEM), new coil as one of the terminals was corroded, new air filter, new fuel filter, transmission filter and fluid change, and supercharger oil change. It currently has about 59,000 miles on it.

No service engine soon indicator, and I probably will have time tomorrow to check for any stored codes. My son has a spare ICM that I may try to see if that improves things, but as it only happens once every couple of weeks, it will be a while before I know if that improves things. Any ideas as to what this may be? Thanks for any help you can provide.

There is a large difference in our years. But i'm sure something is related.

After peeling out [a real one, not a peg-leg], and something worth telling people about, after the tire slip was done, I would still have my foot to the floor, the car wouldn't accelerate, the RPM'* would stay steady, and so would my speed. I would let off the gas, repress the pedal to any position, and all was well. All in all, the only thing our cars share, is that we both have an engine and transmission, and I'm leaning towards the tranny. Although what is wrong with the tranny? I have no clue. My FSM shows absolutly nothing on this issue, so I am sure it'* a freak/abnormal issue.


-justin

I had a 92 se that did somthing similar. I had a bad cam sensor. At most any speed, the car would greatly hesitate and stall when I tried to quickly accelarate. Although, my check engine light came on alerting me of the problem. Otherwise, the car ran very well.

I had an 89 Bonneville SE for several years. Was about the best car that I've owned. Sold it to a friends daughter who just sold about a year and half ago at 200,000+ miles and still going. With all the recent postings on transmission problems, I have to admit it is at least a concern, although I was hoping that the rpms remaining steady might rule that out. Although, I'm not sure I'm getting an accurate reading there.

When it happens, I'm not trying to quickly accelerate, just enough to keep a steady speed, llike on a slight upgrade. Instead of holding the speed, or increasing a little, the speed drops. If I then ease off on the gas, and then depress it just enough to try to get back to speed, everything is fine.

Thanks for your replies.

Checked for stored codes. As expected, there were none. It happened again yesterday afternoon, this time I tried stepping harder on the accelerator. Once the boost reached about +5, it took off again. Still no change shown in the rpms while the problem is there. Shows steady right around 1800.

Ya got me.

I figured I would post my problem.. just in case they were related. Even though they are far from being the same, they technically may come from the same problem at hand.


-justin

I appreciate your input. I've got a lot of people stumped on this, and apparently most here in the forum. I stopped by a local repair shop where I buy my parts, and ran it by their mechanics, too. We're all rather in agreement that it probably is not an engine issue, as there is every indication that it continues to run. (Boost working, no indicator lights, power steering ok, etc.). That does point toward a transmission issue, but they didn't have a clue as to what in the tranny. I stopped by a tranny shop this morning to run it by them and maybe get the tranny scanned, but they're closed for deer hunting season! I may try another shop on Wednesday...so, I'm going to follow-up on your advice.

I've read a lot of symptoms that sound very similar to yours and were all caused by a faulty gas cap or a cap that is not tightened properly. May be something worth while to check into or just replace.

I don't know if this has anything to do with what your problem is, but a buddy of mine has an '02 S10 and he had intermittent shut downs at various different times one day and he thought to just check the gas cap. Problem completely disappeared when he tightened the gas cap. In his case, there were no codes set and nothing seemed amiss.

Good luck and I hope it'* something as simple as the gas cap. The cap should be tightened until you hear it click a few times, fyi.

I'm certainly willing to give a new gas cap a try. From a lot of the postings, it would seem that will be necessary sooner or later anyway. I know that at least 4 of the occurrence happened with virtually a full tank of gas. I already make sure that I hear at least 3 clicks when I replace the cap. Maybe I'll increase that some as a test. Anything'* better than a major transmission problem. Thanks for the info.

Almost all GM vehicles to my knowledge would throw a light if the gas cap was gone or too loose......But that'* what I've been told, now I have never experienced anything like that nor have I ever heard of intermitant shut downs contributed to anything with the gas cap....IU know on older vehicles that don't have vented caps, that could be completely true. Our '03 van at work went 2 weeks with out a cap cuz some dolt left it at a gas station and never told anyone. But there was never any SES or other problems with that vehicle when the cap was gone