Its an e-150 5.4 2v van (I know this is an f-150 forum but not much traffic in the van forum) you drive across a really wash board road or a rail crossing and the van will miss and barely run it sets the following codes p0405, and a p0452 it also will have a p0340. This was diagnoisted 2 years ago as a loss of 5v reference voltage. The pins coming out of pcm where shimmed and later the pins where replaced. This was good for a little better then a year. Drove over a rough rail crossing a week ago and it is back a vengeance. Worked on it some tightened some pins. Better for now. attached is a forscan log of last nights test trip there was one flutter. The FSM says dpfe voltage should not drop below .2 volts as you can see
there is a small amount of time when it was zero. and i believe it caused the fault spike and ftp faults. Any ideas on how to fix this or pinpoint the culprit.

 

Sounds like you need a new PCM my friend.

 

I have put a numbers matching PCM in it and no change in behavior.

 

I may be oversimplifying, however: Take the doghouse off, start it up, shake wire bundles one by one. Might get lucky and find it.

 

Thats kinda where I am at now been chasing that circuit with a VOM

 

Which code shows up in the freeze frame data?