88GTBlack

Its getting 12ish mpg and its got a hiccup at idle. It shudders at light throttle with low gas, but a full tank fixed that. Why does it run like crap Idle is fine no idling issues high idle nothing like that.

Only problem is the terrible gas mileage and the hiccup at idle. Think the distributor is out of sinc? Whats it sound like to you? Im going to try a new ecm ive been posting on here for a while im out of ideas.

Cold it hesitates before revving, smells rich. Its got a fairly new cat so it shouldnt smell.

Hot it hiccups at idle otherwise drives fine. Not a missfire, but it does have a random miss at times its only one hiccup every 2 or 3 seconds.

Fixed all vacuum leaks in previous threads, i went to Pic a Part and drove my XJ in the back and just copied their setups, even took their vacuum lines

Im out of ideas....Any Renix gurus out there?

New fuel pump, seefoamed 3 times, plugs wires cap rotor, only 148,000 miles. 89 4.0liter

XJ_SPORT

Have you checked out the fuel system cause mine did kinda the same thing when ever i wanted to get into the throttle it would hiccup and i would have to let off a little then it would catch up, my problem was the fuel pump had been tearing itself apart from the inside and it resulted in really bad gas mileage (<10mpg)

88GTBlack

did you have a bad fuel pressure regulator? ill pull fuel pressure today ill let you know what i got