Did a rebuild of the top end of the engine. All gaskets, cylinder heads, freeze plugs and all the gaskets. The engine will run and idle as long as the vacuum hose is unplugged from either the pcv or the brake booster. Soon as they are plugged in the engine idles down and dies. Replaced several sensors including IAC and crank sensor. Any help would be appreciated.

 

Did you reset the PCM after changing the IAC?

 

How would I reset the pcm?

 

Just disconnect the battery for about five minutes.

 

Well it didn't have a battery for 8 months so I think it's been reset.

 

Is the new IAC before, or after, the battery was hooked back up? How long has it ran since being put back together? Hows the air filter look? Do you have the tube from the filter housing to the fender installed? Did you remove the mouse nests first?

What brand IAC is in there? Check engine lite on?

 

Engine light was on, it is not now. I'll be borrowing a code reader tomorrow to check the codes. IAC replacement was before. Then the engine was removed and we did the top end rebuild out of the truck. It's been run for several minutes several different times as we have been checking different sensors and such in an attempt to find the problem. the air box has been completely removed and we have no tried re-installing it however before the rebuild I had the same issue with the idle with everything hooked up like factory with a new air filter in it. No mouse nests have been found.

 

May not be a problem to find...... Try this.....

Reset PCM.
Once the battery is hooked back up, turn the key to "on", but, don't start the engine yet.
Count to ten. Slowly.
Start engine.

if it fires right up, see if it will settle down, and idle on its own. If it won't, just BARELY step on the gas, to keep the engine running for a few minutes. Then see if it will idle on its own. If it still wont, start checking the IAC, and the control circuits for it.

 

Ok also the distributor was replaced. It has to be turned completely to one side...turning it clockwise otherwise the engine will not run at all. The distributor should not be tapped out to either side for proper timing should it?

 

Distributor doesn't control ignition timing at all, it DOES control injector timing.... There is a procedure in the factory service manual for 'fresh' installing the dist. I would suggest you walk thru that process, and see if it doesn't improve it's attitude some. If fuel sync is far enough off, you will get some truly strange performance problems.