Code P0300 sputtering and cutting out on long hills

I have a 97 T&C 3.4. The engine will start running rough and slow down until it won't run anymore. This has happened twice and on an extended trip while climbing a long hill. After it cools for about 20 minutes it will start and can get it running down hill. After about 5 minutes of running down hill, it will resume normal running. This last time I checked the DTC and I get random/multiple Cylinder misfire detected. It acts like it is running rich or lean... the engine runs slower with more pedal. I'm wondering if a sensor is heating up and causing the computer to act eratic. This has only happened twice and it is only when loading the engine on an extended hill. Has anyone seen this problem or have any answers for me?

... Rob

usually the cause of a misfire is either a spark problem. Though, I don't believe you mentioned it, but another problem you could run into is a bad throttle position sensor and/or manifold absolute pressure sensor; though if those were bad, you would have DTC's for them, but it wouldn't hurt to check them to see if they're giving you intermittent problems.

usually the cause of a misfire is either a spark problem. Though, I don't believe you mentioned it, but another problem you could run into is a bad throttle position sensor and/or manifold absolute pressure sensor; though if those were bad, you would have DTC's for them, but it wouldn't hurt to check them to see if they're giving you intermittent problems.


My experience with a TPS or MAP sensor is that they just usually go out and stay out. The only time this problem has happened is on an extended hill under heavy throttle and only twice in the 10,000 miles that we've had this van. The weird thing about it is that after a cool-down it corrects itself which is why I believe it may be heat related? It doesn't just go out, it slowly gets worse until it will not even run at all. It's like it's saying "you're pushing me too hard up this hill and I'm running out of energy and I'm going to stop before I get to the top".

Catalytic converter? Just a thought.

It's more of an electrical-cutting-out thing instead of a smooth slow-down. I'm not sure what would happen with the catalytic converter. Do you think it may be plugged, or plugs up when it gets too hot. Is there a sensor in it to read the temp? I know they get very hot. What is your experience with catalytic converters?

... Rob

I haven't had any experience with the cat going bad on a Caravan. We had one go bad on a horizon once though, it made a sound like a tire flapping a chunk of retread when it was going, engine was chugging hard, and when we parked at looked at it, it was shooting little metal marbles out the tailpipe.