1996 5.7l truck code p1345 runs rough when warmed up

[rhensonsr]

3 weeks ago, I bought a 1996 ext cab Chevy that runs like a dream when the engine is cold, but runs increasingly rough as the temp increases.  P1345 comes on as soon as it is started.  Today, I drove about 10 miles until it died.  Since it would not start, I thought it was the timing chain but when the wrecker driver arrived (1 hr later), it started up and ran like a dream.  Here's a list of what I have replaced: cam sensor, crank sensor, fuel filter, plugs, wires, cap, and air filter.  No coolant loss noticed yet.  Any help is appreciated.

[Jsdirt]

It's acting like either the new cam or crank sensor is bad right out of the box. Certainly wouldn't be the first time in the 21st Century ...

 

Make sure that cap is on tight, and none of the hold down bolts broke. If the distributor is out of whack timing wise, it can cause this ... but since it's happening only hot and runs great cold, my money is on a defective cam or crank sensor. 

 

Only way to know for 100% certain is with a lab scope, other than throwing a couple new sensors at it and rolling the dice.

[Doug_Scott]

Have you seen this procedure yet?  https://www.engine-codes.com/p1345_chevrolet.html

I found it when looking for the error code you provided.  You don't mention actually checking the parts you replaced. 

 

Repair by wallet is usually the most expensive way to fix something.