darryljr23

2004 GC 2x4 4.0 205000 mi. It has been fine until about a week ago. We were driving at highway speed and lost engine power. It dropped to the point that it could barely maintain 20 mph. I have checked obd codes with a scanner. Initially threw p0155, p0135, p0302, p0304. I replaces o2 sensor 1b1, spark plugs, map sensor and fuel filter. I checked fuel pressure showing close to 50 psi. The temp differential on inlet and outlet of all three cats is less than 15 degrees F. Also flashed the pcm. Currently it will start and idle, but any increase in throttle seem to bog down. It won't achieve 3000 rpms while parked as it bogs. Water temp is running toward the high side after it runs 5 mins. I have searched and researched and am at a loss. Any suggestions/help would be greatly appreciated. Thanks in advance.

czettlera

Hi I'm not really familiar with the younger Cherokees, but the low rpm, and the high temperature and the loss of power seems to be an ignition problem. P0302 and P0304 also says the same. I would check and change the sparks itself, and if the 04 cherokee also have a mechanical distributor, i would check the contacting points and clean them if necessary, or change. If it's fully electronic, check the coils. I hope it will help.