96 trooper (us) 2.3 auto pt 4x4
Truck idles at 2.000 rpm after running a while. Shut off motor, count to 30, restart motor and it idles fine. Until it does whatever it is doing again. Repeat indefinitely.
I replaced IAC valve. PCV valve. Checked EGR valve (unplugged it). What else could it be? It's not gaskets - they leak or they don't - they're not intermittent.
Power brake booster?
I'm stumped.
Help appreciated?