I have a 2008 ram 1500 4.7 with 280k miles. I drive about 1k miles a week and for the past 2 weeks I have had an issue where my truck will die without any warning or indicator. Only the engine shuts off and putting in neutral turning key off and back on and it runs again like nothing happened. Sometimes it will happen every 10miles or so and other times I can go 100miles with no issues. Doesn't matter if in Reverse, or driving 80mph. Seems completely random.

I have a new battery, replaced the TIPM, thinking of replacing the ECM next but not sure.

Any suggestions?

 

The intermittent nature of the problem is going to make it fun to actually find..... Could be the PCM, could be a failing sensor, and there are a bunch of 'em that could cause this...... Can you do data logging??? Is the PCM setting any codes?

 

I do have an obd2 reader that connects to my phone. I have tried monitoring things and don't seem to catch anything out of the normal. I don't get any codes or lights acknowledging the problem.

I do have codes for my o2 sensors on both banks, have changed o2 sensors and I don't believe my catalytic converter is bad so haven't figured out this one but have had this issue for 100k miles. It does seem to effect my mpg but with this many miles it's hard to say.

I really want to see how many miles I can get out of this truck before I get a newer one.

I just realized today I can see my fuel pressure with my app so will monitor that and see if I can log some more data.

 

What O2 codes are you getting? If they are related to the 5 volt bus, that may be your problem...... LOTS of other sensors also want that five volts, and if they don't get it, the PCM gets confused, and doesn't know what to do. So, it does.... nothing.....

 

P0420
P0430
P0132
P0152

My truck will run sometimes for 400mi without any codes and other times 50mi. I clear them out often so I can recognize a new potential problem.

 

Ok, whining about catalyst efficiency, and voltage high..... Try driving it with them unplugged for a while, and see if the problems go away. (the codes sure won't.... along with a few others. )

 

Hope you used NGK/NTKS senors like oem sensors and not Bosch or something else ,, but with those codes I would check wiring harness closely thats running to all the 02 sensors for frayed / shorted wires ,, since its so random it may be a shorted wire somewhere

 

I did use OEM sensors. Don't really see how o2 codes have anything to do with my problem of randomly shutting off. Would like to get back to the original problem.

 

It's the 'voltage high' thing that makes me suspect the O2 sensors. If the five volt bus is actually 12 volts, then the PCM is going to be REALLY confused about readings from ALL of your sensors.

 

Thanks for clearing that up. I can do mechanical things with help but am far from being a mechanic. So you recommend disconnecting the o2 sensors and driving in that condition to see if anything changes. Since my truck is mostly in a closed loop state I would assume it wouldn't effect performance not having o2 readings.