Monte Carlo Forum - Monte Carlo Enthusiast Forums - 01 coughs, sputters,dies after driving 5 min

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01 coughs, sputters,dies after driving 5 min

After driving about 5 min. car sputters and dies. No check engine light.Fuel pressure OK during
warm up.Haven't checked it when problem occurs.New Relay didn't help.

You have the 3.4 or the 3.8?

As stated...no check engine light.Replace fuel pump?

I'd grab a fuel pressure tester, and leave the car running. See if the pressure drops when it dies out. I had a similar problem, and it wound up being an air intake problem, not a fuel pressure problem.

Sounds like an o2 sensor issue I had once. That would have thrown a code though. I have to wonder if maybe you have a partially clogged fuel filter, and you’re getting pressure as long as there’s no demand. I would also try to get it to throw a code with some vigorous driving. Don’t hammer on it but put it through it’s paces if you can without getting too far from home. h

You'll have to check fuel and spark when this happens. I'd check fuel pressure first. Double check the fuel pressure regulator and see if it's leaking and put in a new fuel filter if you haven't recently. Good luck

Curious for a little more on the description. You state after about 5 minutes the car sputters and dies?
- Anything unusual about the exhaust? Such as lots of white smoke?
- Will it restart after it dies?
- How does it run before it dies?
- Does it die just idling or do you have to be driving?

- Anything else unusual?

I'm curious if this is a sensor related issue. That it dies after the PCM engages information based on a particular sensor.
One example is the MAF sensor. When this guys fails, it can cause unusual failures, including unexplained engine stalling. More known on the 3800 than the 3400 (to my knowledge way less common on the 3400).

A common method to "check" the MAF is with the car off, unplug it. On the 3400, this is a big item that is between the air box and the throttle body (air tube goes from the box to the MAF and another tube from MAF to the throttle body).
Side note, on the 3800 disconnecting the MAF is OK for short term (simple diagnostics). On the 3400, should be the same, BUT, I am not sure if the 3400 Monte vs 3400 in a Grand Am share this in common. I know on the Grand Am, when the MAF is disconnected and the computer pops a code for the MAF being disconnected, the transmission shifts are very harsh because the computer increases the line pressure. Not sure why. And I don't know if GM did the same for the Monte. Sooooo, if you disconnect the MAF, go for a ride and notice the trans is feeling really bad, this is probably related to disconnecting the MAF. And if it does, limit your driving to just a quick diagnostic (prolong driving a trans like that is not good).

Considering the 5 minute delay, enough time for the engine to warm up, I would suspect a bad ECT sensor. If bad, air/fuel mix will be off after it reaches operating temp. It won't necessarilly throw a code either. Does the car stall during driving when coasting?