I have a problem that really has me stumped, My truck runs perfectly for about an hour, and then all of a sudden for no reason it starts to run like its only running on two cylinders really bad,
It did this before once and I replaced the distributor, coil, wires, plugs, cap, etc. and that was four months ago, and that solved it, and now here it is doing it again now.
The idiot light is flashing when this happens for a while and it shows codes 300 multiple misfire (duh) & 345 cam crank correlation.
The last go-around cost me nearly $900. and I can't believe it needs another distributor !!
Looking though my shop manual, I see a Coil Driver module, thats located on the same bracket as the coil, could this be the problem ?
Also is the Cam sensor part of the distributor, or can it be replaced seperately ?, I tried another new coil and that didn't help, thanks for any help I can get
AM

You may need to get your ckp/cmp correlation code fixed at the dealer or someone with a scan tool. The timing needs to be adjusted with the scan tool to fix the P1345 code.

thanks but the timing has been checked and is correct, whatever the problem is takes an hour to develop.
AM

I've read that 5.0 & 5.7 have a prob. with oil ascending up
distributor shaft causing misfire and new shaft with reverse
spiral fixed prob. Oil under cap is a clue.
?

Well thats one I've never heard of, going to check that out over the weekend for sure, thanks.
AM

It's a long shot, but I figured worth mentioning cause you
said new dist. solved prob. for a while. The tech article says
new shaft P/N is 10467353. Also says "GM determined
some dist. shafts were improperly magnetized due to the
magnetization with the rotor on the distributor" - 5.0, 5.7 & 7.4
Good Luck

Thanks for the info, definitely going to look that one up.
AM

Well I checked out the distributor over the weekend and its dry as a bone inside, nothing in the cap, or under the rotor, or near the cam sensor, and its still doing it so, I'm still stumped.
Thanks anyways.

Just for everyones info, the problem turned out to be the new cam position sensor, in the new distributor had failed, (2 months old) The shop fixed it under warranty, glad to see that issue gone !!!!!!:)