Just as the title reads. I have a 91 4.0 and it had a high idle. I used the carb cleaner trick to locate a leak at the intake/exhaust manifold gasket. So after several hours of cursing along with some blood, sweat and almost tears, the new gasket was on. Pretty ridiculous that I had to take off the power steering pump and bracket to get the intake and exhaust manifold off. Anyway, I put it all back together and checked everything and now the Jeep idles at 1500 rpm. Suggestions? I tried to make sure there wasn't a vacuum leak and didn't find anything. I did find that the exhaust manifold has a crack in it where the tubes come together. I'm at a loss. Is there a way to adjust the throttle? Also, it smells like it's running a little rich. Any help would be greatly appreciated.