I need your help, please. i blew my original 4.0 (RIP) at 280K and bought a salvaged 4.0 and it's exhaust header was different. When I pulled the headers to swap, the engine started at idle, but immeadiatly the RPM increases uncontrolablyover 5K in the blink of an eye! The throttle was never touched. I shut the engine down before it blows. The oil pressure barely starts to climb and feed the upper end before I have to shut itshut it down. It's not long enough to throw a check engine code... Extreme high RPM at start up after engine swap