Mdjeep

I just replaced lifters in 2002 grand cherokee 4.0. I put everything back together and when I start it it want to rev to the max. I retorqued intake, checked all electric connections and vacuum hose. Any ideas on what would do this?

Ive checked all vacuum hoses. When I unplug map sensor. It does not rev high just runs bad. I can control throttle with peddle it just misses bad. This is not making sense at all.

dave1123

Are you sure you have the map sensor hose plugged into the correct vacuum port?

Bustedback

Take another look at the intake, you have a vacuum leak.

Mdjeep

The map sensor was never removed I removed intake and re-attached with same results. I will look into it more this weekend. I figured a vacuum leak but can't locate it.

dave1123

Just as a point of information, when I replaced the head on my 4.0, I put in a new set of Sealed Power lifters (175K miles) because I thought it was a good idea. My "4.0 rattle" was gone, but only for about a week, then it returned. Oh well, 4.0s just rattle, I guess.

Check the throttle body base gasket. It may have developed a leak during handling.