coyote121403

So I have a 91 XJ, I just replaced the head about a month ago. I can drive it for about 30 - 45 minutes and then it will start sucking and sputtering and then dies. If I let it sit for about 15 minutes it starts right up and goes down the road. (seems to work faster if it sits pointing uphill). I thought fuel pump but if it were it wouldn't run. Temp is just over half way on the gauge as usual. Also dunno if it's related but since I changed the head the defrost vents are all that works. I was gonna go get a $90 diagnostic but whats the point if its running fine when I take it in?

offroadnut36

If it was the fuel pump it would sputter going uphill, not work faster. did you make sure the timing was right when you put the head back on?

coyote121403

The timing should be correct. Didn't mess with the chain or anything when changing the head. It purs like a kitten for 30 mins then sputter for a few secs then kurplunk...

jd4x426

did you change your fuel filter if not try that sound like it might be clogged

coyote121403

Another note if it helps; when it dies if I go to open the hood, the hood is so hot I almost have to use a cloth or gloves to open it. I will check the filter, thanks!

Dan4governor

for the defrost, you have a vacuum leak in your system. Check the hose that leads to the evac unit (the pill shaped thing on the inside of the front bumper on the passenger side). That line is usually the culprit. You can check because if that line has a leak then your heater won't work either.

BuckB91XJ

This may ot may not have anything to do with how your Jeep is running but, look down inside the passenger side of the front bumper. You should see a small black plastic ball about the size of a softball. Make sure this ball is intact with no cracks or holes in it and make sure the vacuum line is hooked up to it. If this ball is cracked, broken or the vacuum line is disconnected, it will cause your heater vents to freeze in the defrost position like they are. I would imagine it would also cause a heck of a vacuum leak which could explain why your Jeep isn't running right.

coyote121403

What is the hose that comes out of the top of the valve cover to the intake manifold? This hose does not seem to be attached correctly (its loose) at the valve cover.

coyote121403

So I checked the hoses and tightened them up on the intake manifold, now the vents blow air but the jeep still stalls after about 45 mins of driving. It seems to do it right after the temp gauge passes 210. It never gets into the red or even past 3/4 mark but it gets hot. Can this be whats causing it? Does fine driving down the highway but city traffic it dies.