I had my 5.2 engine replaced about 1000 miles ago with a reman. Since that time, it has been raising a P1391 code - intermittent loss of camshaft or crankshaft position sensors.

Engine runs great at all speeds.

Ok, easy I thought. I replaced the crankshaft sensor first, becuase it appeared to not work when i manually turned over the enginer while back-probing the sensor. No dice.

I then replaced the camshaft sensor. No dice.

Both sensors are getting the 5V in, so now I am stuck.

Am I looking at an intermittent short possibly? One intersting thing I noticed. In 2 recent trips to Florida, the code would clear after a day or so driving there. Once I returned to Ga, it comes right back. Thought maybe it was due to heat or humidity that is affecting the wiring.

Anyone have any ideas?

Thanks,
Randy

 

Try wiggling each of the connectors to the cran and cam sensors while the engine is running and see if you can hear the RPM's fluctuate. Make sure these connectors are making good mechanical connection, sometimes the terminals inside the connectors get a tad loose. Use some dielectric grease on the termionals before you snap the connectors back together. Also check the terminals and connector at the computer.

 

Where is the camshaft sensor I the 5.2 located?

 

Under the distributor cap. Parts stores will call it "Pick up coil".