I have a 1994 ram with a 5.9L and automatic transmission. I bought it in april while the weather was still cool and drove it everywhere until the first of june without any problems. I left for vacation and returned in july and was driving it at 60 mph and it stalled out...engine would turn over but would not start. Had it towed home. Got home 2 hours later and it started right up. Drove to town the next day and it started to stall while in park (idling) and at stop lights. Overall, I have noticed it stalls only after it has been driven/idling for 45 minutes and has reached operating temp. I have replaced air filter and have removed and cleaned both the throttle body and IAC sensor. I then let it sit in driveway just idling and after 45 minutes it stalled again...so I ASSUME the problem must have something to do with some part getting hot. I am wondering WHAT THOUGH? Please let me know what you think? Thanks

 

unless someone has a better idea, in a case like this, you might be better off taking it to someone with a scan tool, so that when it shuts down, they can see what's not functioning.

as far as troubleshooting,
it could be something related to fuel pump, relay, or the fuel shutdown. you could test this by pouring a small amount of gas down the tb when it won't run.

you could test for spark at the spark plugs. it could be a bad coil.

then again it could be any of several sensors.

if i had no other tools or ideas, and was just going to guess, i'd check for spark at the plugs, and if none, replace the coil.

 

I had something similar happen on an old Mustang I had, and it turned out to be that the coil was getting too hot.

 

Sounds like you're having a converter problem.As the substrate in the converter hets hot,it swells and will cause this problem,Once it cools,it will shrink again allowing exhaust to flow through and let the engine breath.

Get the cat tested.

 

Similar but different than my problem. My 99 dodge is(/was?) dying with no diagnostic codes. My shop's tech told me that if it was dying when stopping and starting that the first thing he would replace was the idel air controller (easy to get to on the throttle body) and if it was dying while going down the road to replace the crankshaft position sensor (PITA to replace) and of course mine dies while going down the road so I replaced it. Now I just have to drive it until it does or does not die again while considering other options such as the pre-cat o2 sensor. Good luck, Frank

 

Thanks guys. The truck does NOT throw any codes. I know the when I bought it, I found that the catalytic converter has been replaced three times (found some service receipts) so I am wondering if the last owner had the same problems with it...I don't know who that was otherwise i would ask them. So, I am wondering if that would mean it has gone bad again or if it might be a different issue. Like I said no codes when it stalls and has stalled at idle and while driving 60 mph...both at 90+ degree temperatures outside. WOUld it have anything to do with the PCM getting hot? Thanks

 

One other thing...don't know if this helps, but when I parked it and let id idle until it died (after 45min-1 hr) I opened the hood and noticed there was like a light haze of smoke seeping out of the air box on top of the throttle body...is this normal? I haven't noticed before when it has died while driving so was wondering if it was since it was just sitting there idling.

 

My first thought is fuel pomp is going out or filter needs to be changed. Does it have an in tank pump/filter? I would start with fuel then move to air flow. doesn't sound electrical.