I'm with RAVRAM on the timing. I don't have the vehicle but I will bet that if you change the PCM you will still have the problem. The PCM catches the blame most of the time when people can't figure out the real problem. Do you trust this mechanic? Please explain "air intake valve on the back of the throttle body" that is opening and closing and hissing.

 

the valve on the back i call it the trottle body.mine has the fuel rails with the injectors on it.no in jectors in the throttle.i would just hate to spend the money on a pcm

 

I'm trying to figure out what valve you are referring to. What wires or tubing goes to it and what is the tubing connected to?

 

wires go to it.it is on the backside of the throttlebody.the bottom of my distributor looks like a flat head screwdriver.what is weird it started doing this before i took it apart

 

i think it is called the air controller

 

The IAC valve (idle air control valve) controls the amount of air that bypasses the throttle plate and flow into the intake manifold. Did you mention this to the mechanic? The IAC will cause many of the symptoms you are describing. Total failure of the IAC is easy to diagnose but intermittent problems can usually only be found with an exercising tool (usually dealer only). Without the exercising tool you can easily destroy an IAC with the tests if you are not careful.
I haven't had the distributor out of a 360 but I believe the flat head screw driver on the bottom of the distributor is the oil pump drive.

 

when i had the transfercase out the motor and tranny was leaning back.what is the chances of maybe the crankshaft sensor hitting the firewall or any sensors or wires.it ran fine till i pulled the case out

 

I would think that if you did not support the tranny the back of the engine would pivot down more than rearward using the motor mounts as the pivot point. That being said there is a resistance check for the crank position sensor. Here again did you mention this to your mechanic? I am not positive but I don't believe the engine could run at all without the input from this sensor to the PCM.

 

I can't imagine that the truck would even run if it had a bad CPS. if it got knocked out of position (is that even possible gurus?) I could see the timing being WAY off, but short of that I just can't say with confidence that it would be the CPS.

IAC valve...hmm, is that vacuum controlled? could be the diaphragm has a hole in it and isn't pulling open anymore.. or maybe the line that feeds it got pulled loose and is old and now it's leaking.

So many variables.

Just out of curiosity where are you located?

 

The IAC is electronically controlled by the PCM not the vacuum and there is no diaphragm. The pintle of the valve opens a passage inside the throttle body so there is no external source of air.

The CPS is not adjustable and can not be knocked out of position. The top of the sensor and the wires are vulnerable to damage if pressure from the firewall were applied but here again I don't believe the engine would even start.