Alright so I had a crappy PCM so I bought another one flashed to my VIN. It fixed a ton of issues the truck had so I figured I could drive it some distance now and it stalls randomly. It seems if the engine is cold it's fine, I could give it all the crap in the world and it's good. Drive it for 15 min and it will just die. You come to a stop, turn it off and then back on and it fires up for another 5-10 min. The very first time it did it it had the infamous "no bus" on the odometer. Now when it does it there is no "no bus" and no engine codes or anything.

 

How old are your O2 sensors? Where did you get the PCM from?

 

I got the PCM from All Computer Resources, you can Google the company. I don't think the O2 sensors have ever been replaced, they look dated but not awful. I was thinking of replacing those or the crankshaft position sensor. Is there anyway to test either of them?

 

O2 sensors are actually maintenance items every 60 to 75K..... they still work, they just get slow, and inaccurate. The PCM doesn't care, so long as it sees readings that make some kind of sense. (though, how it defines "sense" is a mystery.....) Go with Denso, or NTK sensors, our trucks don't really care for the Bosch sensors.

Your symptoms correspond to failing O2 sensors though. The PCM ignores them for a few minutes till the heaters can bring them up to their operating temp....... so, initially, they don't play a role at all, but, once the PCM starts paying attention, if the sensors are lying, the computer STILL bases its fueling decisions on that data... Easy test to simply disconnect the front O2 sensor, and go for a drive. If the symptoms disappear..... bad sensor. (it will set a code that way though....)