it will sstart redline itself and we shut it off before it blows up...and other times it doesnt start at alll

Sounds like a stuck throttle body. I would check the TPS make sure it'* not messed up. If it'* going to high RPMs, then it a throttle body problem or a sensor on the throttle body.

apparently yj'* didnt get the 4.0 till 91. the xj had it in 87, anyway disregard and carryon.

he said its carbed, sounds like a leak in somewhere between carb and head if the airs not controlled

what about the broken tube....it ran jst fine we pulled it in the garage before but that tube got broke and ebay is the only place to find one why is a rubber hose not working???

That broken EGR tube would let a lot of air in and cause a high rev. Plug it. That will at least stop the vacuum leak.

alright...thanks guys i slept from 330 am to noon but im still tired thanks alot Dan and JW

im not sure about the tube your talking about, i havent worked on a 4.2, but my old neon did that one time i had a self inflicted air leak between the throttle body and intake. it sounds like you have a leak, maybe that tube, maybe not

good luck

it should be the tube sense we replaced all the other gaskets i even torque everything lol

hopefully thats all it is.