Bought a 2001 XJ last week. 175k 4.0 few body blems. for 2700. got a few questions. Ok first off it starts runs and drives well. plenty of power, no misfiring, runs like a champ. got a few concerns though. when you start the XJ while the motor is cold the Oil pressure reads 40-50 at idle until it warms up and sometimes it will drop down to ten and then every once in a while it will drop to 0 but it still runs fine. im thinking the sending unit. second. the temp seems high to me it runs between 210 and 220. never above 220 though. third in 4hi or 4lo when turning it clanks really bad. i know its normal for a small clank on hard surfaces but it does it no matter if im in mud or on black top. 4th. from a stand still when accelerating it jerks almost feels like the drive train needs to wind up or its taking slack out of a u-joint or something. but all the u-joints look and feel good, no slop at all.

sorry for such a long post. just had some questions. thanks for all the help in advance. here is a vid of the jeep.

http://www.youtube.com/watch?v=http:...?v=mUf-SbRjUXc

Wrong thread, sorry

 

I will address your oil pressure issue its is very similar to what mine was doing. Could be bad (coolant in the oil) to low idle speed, or a bad sending unit. First things first get a mechanical pressure gauge and verify those oil pressure readings, or just swap the sender out, but warm low oil pressure is consistent with either a worn oil pump or bearings clerances. Mine ended up being excessive bearing wear from coolant in the oil. Take an oil sample and send it off to Blackstone Labs they can confirmt he presence of cooling in the oil, yours is the right year to possibly have a cracked head worst case.

You could also try a heavier oil like 15w-40 or 20w-50 and that may improve your oil presure when warm.

Your Temps are just fine, the electric fan is designed to kick on at 217-218 so you dont have a problem there.