Just picked up a 87 454 4dr dualie, upon purchase, truck idles about 2500 rpm and had horrible part throttle manners.
Found throttlebody gaskets to be bad - both of them real bad.

After fixing, idle came way down to normal ranges, but still dies when in gear and part throttle is still bad..
Removed IAC and cleaned and seems to work fine, and can hear on initial startup..

Also manifolds are real real hot, like 700 surface temp and smells rich - checked after noticing extreme heat under hood.

Since this problem I have changed plugs, wires,cap,rotor, Removed cat and made free flowing 3" exhaust (Fur fun, Checked EGR - moves just fine, Scanned to check BLM, IAC,TPS,Park/Neutral switch.. Checked timing.. and changed O2.

Everything seems ok, no trouble codes present...

Did find that after removing ESC wire truck idles in and out of gear just fine until you restart then starts missing and stalling... Im guessing it idles because its in limp home mode when wire disconnected.
Tried timing about 20* each way just to make sure, no change for better.


Any thoughts?

Truck runs great WOT, horrible part throttle.