XJ711

Finally got my 00 xj started yesterday...it's hitting close to 6000 rpms within 2secs of letting it run...any idea's on what could be making it do this...throttle linkage is fine...cables are releasing, pedal isn't stuck. I haven't changed any sensors yet. I'm going with tps sensor, or idle air control?? Any suggestions would be greatly appreciated.

TheJerm

I would remove throttle body and the IAC (idle air control) from it to clean out both. Be careful cleaning the IAC

SeriousOffroad

Grab a flashlight and climb under the rig. Look up at the manifold mounting surface and determine if you have the correct gasket. There are two configurations available.

High RPM's on start up are an indication of a massive air leak on the intake side of the motor.

XJ711

While I'm thinking about it...if anyone has an tips of things that need to be done...or adjustments that need to be made to get the engine fine tuned...let me know...I was just reading another post and someone said something about haveing the fuel injectors turned to a certain degree...stuff that i didn't think to look into...such as that...would be helpful.

Yeah...about the application of the manifold gasket...i have come to find out that...even with a 2000 and 2001 engine, there are some suttle differences.

the_big_h

Fine tuning? I think that 6000 RPM at idle is gonna need more than a little "fine tuning".
TPS sensor just tells the computer how far the throttle is open. There is no way it can make the engine do 6 grand.
IAC just opens a port around the throttle plate. I'm pretty sure the port is too small to let enough air in to get up to 6 grand.
Have you looked down into the throttle body, to make sure the throttle plate is fully closed when you are off the gas pedal? If it is fully closed, then you have a massive air inleak somewhere. Are all the vacuum hoses hooked up? If you had the intake manifold off, it's fairly common to get it not seated properly over the locating pins, leaving a gap between the manifold and the head.
You could try starting it with your hand fully covering the air intake. If it still revs high, it has to be a leak from manifold to head, or open vacuum lines. If it won't start, then the throttle plate is not fully closing.