It will take about 10 miles to reconfigure everything. I disconnect the battery after I change something that will affect the engine. How long did you disconnect the battery for? Should try for half an hour, just to be 100% it did put everything back to factory(codes will still be there well some at least)

 

ok, i have drove beyond ten miles at all ranges and had a good disconnect and still no change. Still around 1100 rpm and even bumps up a little here and there. Where to from here?

 

Tsarge,
FWIW

I once blew an intake gasket on an 87 5.0 due to a defective pcv valve. It also leaked a decent amount of oil at the rear of the engine.

 

ill give the truck a look over but i havent ever noticed any real amounts of oil leakage. just minor never hurts to check

 

With engine at normal operating temperature, disconnect the IAC, what does the engine idle at? It should be 400-500 RPM. Make sure the base idle screw is not holding engine at a higher RPM. If screw is not the fault then check for intake leakage using a choke spray at all joints.

 

Good ole Bill,

I did what you said and it does drop the idle some about 750 rpm. I am fairly certain there are no intake leaks i take off the routing hoses to the throttle body and plug the two intake ports with my hand and the engine dies. plus no leaks with a can of cleaner.

 

ok tried good old bills suggestion and it didnt change anything, however........left the IAC disconnected, went out about an hour later started the truck up and the idle is around 500 rpm maybe on the high side of 500rpm. What does this mean? Bad IAC??

 

Still having trouble with this. Cleaned the IAC thoroughly and reinstalled it. If left unplugged on a cold start the engine idles fine at 500 rpm or so until you start driving then it hangs out at 1000 or hihger. If you plug it in it is always around 1500 rpm. Any thoughts