Here's why I had to put in the new head/HG: http://www.4x4wire.com/forums/showf...p;amp;sb=5&o=186&fpart=1

I just fired up the engine after having installed a new head, and I can't get the engine to stop loping. No, not the kind when you've got a hot cam, but the kind that's telling you there's air in the cooling system. Thing is, I burped it, and I'm 99.9% sure there's no air in there. I have one of those T-fittings installed in the uppermost heater hose, and there's no bubbles coming out when I crack it open. The idle won't settle down either (high idle).

Radiator's full. I'm getting full heat in the cab. Timing is set with the jumper engaged. No codes being thrown.

My A/F ratio meter tells me it's in open loop, but when I step on the throttle it goes into closed loop.