Idles at 2800 rpm and won't come out of first, no vacuum or intake leaks, new tps, new iac, new map. About 2 weeks ago after a few hours on the highway it died, and wouldn't run for more than about 2 mins on restart. In the last 2 months it's had a new fuel pump, manifold, downpipe, muffler, both o2 sensors, coil and wires, crank sensor, air filter, cleaned throttle body, and every sensor on the tb. It's a 98 4.0 with 180k miles. I'm out of ideas, hopefully someone else does!

 

you sure about this ? otherwise something is chocking the tb open.

 

Sprayed carb cleaner all around the intake and tb while it was running and it had no effect, checked every vacuum hose I could find and they all hold vacuum

 

How is your idle air controler?