1999 G1500 5.7 Timing issues?

[krumrei]

We are working on a 1999 Savana with about 80,000 miles on it.

The engine is popping and blowing airback out the throttle body, as if it was out of time.

We hooked up the computer and came up with a P1345 Code which states that the engine could be out of time or the sensor is out.

We replaced the sensors, checked the distributor gears, and checked the cam gears, even looked at all the timing marks and timing chain seems to be a little slack, but not enough to looked as if it jumped positions.

Anyone have any idea what else it could be, looks like everything we trouble shot with the timing is correct, other than the slack in the timing chain.

The engine still pops and blows back the intake/throttle body as if it was out of time still.

Any help is appriciated!

Paul Krumrei
Minnesota.

[maxwedge]

This may idicate the cam pos sensor is out of synch with the crank sensor a full service scanner can check the synch percentage error. Did anyone move the distr.? The rotor must point exactly to # 1 contact at tdc @# 1 firing.