I have/had this same problem. Over the last month or so my truck seemed to have lost a bit of power but it was not that noticeable. My gas mileage has also been down by maybe 1 MPG. I drive 40 miles round trip to work 5 days a week. Day before yesterday I drove the truck to work and home from work, all was fine. Had dinner at home and went to the store with my wife, store is only about 2 miles away from home. When I pulled in to the store parking lot my engine shut off. I was able to start it right back up again and thought maybe I had not let the clutch out smoothly enough and that caused the stall but also had a suspicion there was some other problem.

Yesterday morning I drove to work, no problems at all. At lunch I went to the DMV to renew my registration, it is only about 4 miles from where I work. I was in and out in maybe 10 minutes, came back out to my truck and it would not start. I tried it a few times, no start. Then I waited a minute and tried it one more time and it started up. I drove back to work then home yesterday without any problems but it still seemed a little slow and sluggish. It started when I left work but took a little longer than normal to fire.

Last night I checked everything I could on the truck, scanned it for codes, no stored or pending codes came up, scanner gave a green check "all is well" status. I removed the coil and the primary was .3 or .4 ohms higher than the specs allowed. Secondary was OK, within normal specs. I got a new coil and installed it and the truck seemed to do much better. It started right up, had much better and smoother idle and felt like it had more power when I test drove it. It started better and ran a lot better going to and from work today too.

I read online that stalling after a short trip can be a sign of a bad coil. I reasoned my coil could be bad based on that and the out of spec primary winding. I also read that if you have a bad plug, plug wire, cracked distributor cap or bad rotor button it can overwork the coil and make it weak enough to make the engine run poorly and stall when the coil gets hot. I just did a tune up maybe 3 months ago with new Autolite Professional wires, 3923's, Napa cap and rotor with brass contacts so I don't believe I have any problems there. If the problem comes back I will check the cam and crank position sensors. I may just shotgun it for peace of mind and replace them anyway this weekend when I have more time to work on it.

The cam and crank sensors are the only other things I can think of that could cause this heat-related problem. There is a chance it could be the PCM but I would think if I had a bad PCM, cam or crank sensor it would set a code. I had no codes when my engine stalled Monday night and no codes yesterday when my truck would not start. I am kind of at a loss and scratching my head on this too. Please let us know how you make out with yours Hanneman. I will do the same.

Jimmy

 

Well at least my truck did not wait long to let me know the coil was not the problem..It drove fine this morning but coming home I was about 2 miles from my house and stopped at a red light. Light turned green and I went through the intersection and my engine shut off. No steering, no brakes, but I coasted through the intersection going a bit downhill and got off in the left side turn lane, shut it off and it would not start up again. I kept trying and it would not start but it did set a P1296 code. I checked the code on my phone, it means the MAP sensor is not seeing 5 volts from the PCM so either the PCM is toast or I have an open wire from the PCM to the MAP.

I sat there in the turn lane, hazards flashing, and then tried to start the truck again. That time it started so I babied it home, but it still cut off another couple of times but I made it home. Now I am headed out to see if I can find out what the problem might be. I sure don't want to buy a new PCM but that might be what it takes, I don't know yet. If anyone has any ideas or info I am all ears.

Thanks.

Jimmy

 

Don't rule out a bad MAP sensor. It could be an internal failure.

 

Thanks Dan.. I tested the MAP tonight, it does have 5 volts and ground inputs from the PCM. It has 5.2 volts with the ignition on and key off, and has 1.49 volts with the engine running. 1.49 is at the lower end of the acceptable range so I may try a new MAP and see what happens. Just for giggles I called the Dodge dealer, new PCM is $1,035.00 and they would give me 10% off..I don't believe junk yards sell PCM's but I may call around tomorrow anyway. I am off to Auto Zone now. Thanks for your help.

JImmy

 

You can get rebuilt pcm's too. You just send them the vehicle info and they'll program it to match.

They're a lot less than $1035.00. Junk yards should but you need to make sure all the options match, engine, trans, etc.

 

Thanks again. I replaced my original MAP sensor back in 2008. I bought the new one at Auto Zone. I dug through my receipts tonight but did not find that one. I removed my MAP anyway and went to Auto Zone, figuring maybe they could find it in their computer or else I would just buy a new one. Luckily the Store Manager was there and he took the time to dig it out of my purchase history and they did a warranty exchange on it for me.

I installed the new MAP and cleared the code. Truck started and ran OK in my driveway but I will need to drive it a couple of days to see if the MAP was the problem. My wife is very worried it will cut off in traffic again but the only way I know to test it is by driving it. I checked autocomputerexchange.com, they are in South Florida and I can get a rebuilt PCM there for $240.00, a lot better than the dealer price.

I will post my results here over the next few days. Thanks for your help.

Jimmy

 

I'm dropping mine off with the mechanic tomorrow, likely changing the crank sensor.

Question: Can a crank sensor overheat, stall your engine, yet not trigger a code?

I had zero codes when I ran it after the several stalls.

 

Yes to the overheat and stall. Sometimes the codes just don't appear - for any malfunction.

 

To add to that, many times when they get hot, they short the 5V circuit and wipe the PCM memory out. The scan tool will show the "starts since reset" as 0.

 

I made it to work today and my truck ran fine. Nice smooth idle and even seemed to have a little more power. I hope the new MAP did the trick but only time will tell. I was thinking that if the PCM was bad I would have more codes and worse problems than just an engine stall. I will probably replace my crank sensor for peace of mind.

Jimmy