So after battling the Cyl. 5 misfire for 8 months with the CEL on and off etc. , I think I've got it. The other day I had the van idling for 5-10 minutes and when I got back in the CEL was on. I turned it off, and checked the codes. I couldn't beleive it. P 0301. Cylinder 1 misfire. No sign of 5. By the end of the day, the CEL was off again. So I was thinking it was a bad PCM and now I'm sure. After turning the van on again today the CEL was back. Key dance. P 0601 followed by P 0301. P 0601, PCM internal failure. It's time to take this meatloaf out of the oven. When I have the money, I'm getting a reman PCM and will finally be putting this thing to rest. I hope the rest of you have the same luck.

Thanks,
Bill

 

My codes went away when I simply changed out the cap-n-rotor with a copper/brass contact type. Those aluminum cap-n-rotors are just junk.

Check that out first vs. buying a "new" or "reman" PCM.

 

Already did that along with numerous other things.
My next step was to change out the heads but all things considered the computer is more then likely the problem.

 

I dont want to be a wet blanket but there is a possibility that the bad PCM ran your van lean, which burnt your valves

It is strange to get a PCM internal error and still have the van run. It can happen, so it must be a place in the memory that still dosent affect the operation, such as air/fuel tables, certain inputs like MAP etc etc...some of these things can be omitted and the van will still run.

When my PCM died, the whole van died. Nothing, no start, no spark just blaaaah.

Good luck!

 

Hey Bill what year/model/engine is your van?

I have been fighting with the same CEL gremlin for more than two years now on my '98 3.9L and lately (due to the cold weather, I think) the light has been turning OFF occasionally. I have always suspected a temperature-related cause to my specific problem and this seems to further support my suspicion. But I still don't have my finger on it.

FYI -- I have a spare PCM which I swapped in for a while over this past Summer and it did not change the CEL activity at all. It also reported the very same random misfire codes.

With all due respect I think you will be in for a disappointment if your only aim is to fix the CEL by replacing the PCM.

 

2000 Ram Wagon 3500, 5.9L. I'll get it running right sooner or later. The heads could be bad by now too and the cat probably is. I'm just thinking if the PCM is the problem I'll spend 2 or 3 hundred and know that is or isn't it. If I do heads it will cost more and it could still be a computer problem. Plus I think I'm getting like 11 MPG highway which is terrible and I'm hoping this will also improve with a new PCM.

Thanks,
Bill

 

you can get a cat off of Amazon for 60 bucks, and then find a independent shop to put it in for you. Total cost will only be about 100.

I got my PCM from a rebulid place on the east coast (FL) it was 159.

Also, I found this to be true with my van just a few days ago, the MAP sensor get funny. It wont set a code but will kill your gas mileage. I read about this in may posts here and on other forums. My mileage actaually as gone up 2MPG since I put in the new MAP sensor.

Good luck