96 Monte LS Missing or Cutting out?????

[96MonteCarlo34]

Originally Posted by sierra77

My 96 Monte LS 3.1 (132K) started this a few weeks ago. I noticed it when sitting at a stop light with the A/C running, in drive, foot on the brake. Idles good, but the engine intermittantly jerks like it's missing. I can feel it through the chassis and the tach will drop ever so slightly. I hadn't driven it on the highway for quite some time, but did this past weekend. Took it on a 150mi trip. Started off doing it every so often at highway speed. By the time I was almost at the destination, it was jerking so badly and almost consistantly, that it felt like I was hitting potholes on a brand new asphalt road. It was worse when going up hill and with the A/C on. Didn't do it as much on level ground or with the A/C off. I originally thought before this trip that it might be the Idle Air Control valve. My buddy had one off of his 3.1 that turned out wasn't his problem. I swapped mine out and that didn't help. I put a different fuel filter on this weekend when I got home and that did not help. It doesn't seem like it would be the fuel pump, however i'm not discounting it yet. It almost seems to me like one of the coil packs is going. Has anyone experienced the same type of situation? Or Does anyone have any ideas?
Someone said bad gas, but I don't think that is it, as it's had several tanks full ran through it with the same issue. Any help would be appreciated. Thanks!

Mass Air Flow Sensor??

[Blue Bowtie]

Loss of a MAF signal for as little as 600mS will set a DTC. The PCM watches that one pretty closely.

[Z74]

Im having the same, or similar, problem. I have a 97 monte carlo ls and it keeps dying on me at random times, or seems so. It usually cuts out and dies with no prior indications, typically at a stop sign, stop light, and lately when going down the road and begining to let off the gas to slow down for a turn or another vechicle is braking. Oh and of course it has to happen at the busiest intersection. When it does die, the volts and check engine light comes on (and maybe another light but uncertain right now). After dying it takes 1-5mins of sitting there and it will start right back up and run fine but i try to avoid all stops as possible until i get to where im going but thats usually not possible and it dies again. I put it in the shop week after week with the mechanics guessing, which just costed me money. They replaced the computer, still died; replaced ignition module, still died; replaced crank sensors, still died; redid some wiring between crank sensors and ignition module, still died. I ate money on that and the mechanic(s) ate money on it too cause they didnt fix problem. Thats the problem im having. Only suggestions that ive been told was possible TCC solenoid or Mass airflow, but the ppl suggested didnt sound so sure at all and i didnt want to eat more $$ without other opinions. Thanks.

[sierra77]

Z74,
My Monte never got as bad as yours is. It never died, just kinda chugged slightly. It ended up just being a bad plug. I actually traded it last March for a '07 Camry, but it was running great when I did. While reading your thread, I was first thinking Crank sensor cause i had another car with a 3.1L that did what you were describing and that was the culprit on that car, but as a read on it looked like you already ruled that out. For what it's worth, my parents used to have a '87 Pontiac 6000 SE with a 2.8L in it that did exactly what yours is doing now. Tried to die when slowing down or when the car was turning, and sometimes would sit there for a little while before it would start up again. I remember my dad saying the guy at the shop said it was the MAP (manifold air pressure) sensor. Might be worth checking into. I didn't see it on your list of stuff already replaced.

Here is another idea that is just a shot in the dark: If you slow down to a stop and it starts to chug, if you slip it into Neutral, does the car keep running? I used to have a '92 Cavalier Z24 with a 3.1L that showed somewhat similar signs, and it would chug or die when I slowed for a turn or slowed for a stop. If I shifted into Neutral, then slammed it back into drive when I needed to go (as long as I had the RPMs) it would be fine. It ended up being a Vehicle speed sensor in the Tranny that was basically not allowing it to downshift and it was like trying to drive a 5-speed in high gear all the time.

Good Luck to you!

[Z74]

Thanks for the advice sierra. Ill be sure to look into that this week.

[ReBorg]

Im haveing pretty much the same problem with my 97 monte carlo 3.1l v6 mine is having problems starting once it starts it runs good. clean idle as soon as i put it in gear its ruff and gutless. if i give it more than 1/4 gas pedal it wants to die like it was hitting a rev. limiter. I can barely get up to 30 mph and thats only by feathering the gas pedal. I did get a code for a #6 cyl misfire and also a code for fuel system bank 1 was lean. Not quite sure what thats all about anyone have any good ideas? i feel like im chasing my tail!