LAREDO 4.0L - PO202, PO203, PO204, PO300, PO303, PO304

2000 Jeep Grand Cherokee • 190 miles

I'm at my wits end with this thing. It started running rough at idle only. I changed plugs, which looked ok but changed them anyway with proper copper plugs (these cars are notorious for running badly with platinum). No change. I ran fresh fuel with injector cleaner. No change. I put in a new ignition coil. No change. I replaced all of the injectors, even though they all read 13.2 ohms and checked with a noid light. No change. All the wiring looks ok. One interesting thing: PO202, 203, 204 came up after changing the injectors. Before that I was only getting PO300, 303, and 304. Does this mean a new PCM is in order or is it something else I may have overlooked?
April 13, 2013.

Those codes are injector circuit codes. Did you use new injectors? Hope so.

Did you do a compression test in the beginning?

Were there any other codes? Does it hit on all 6 cylinders running?


Apr 13, 2013.
I used new injectors, all within normal resistance range. Tested all connectors with noid light. I listed all the codes I got and, like I said, the circuit codes came after I changed the injectors. The misfire codes came prior, so I I believe I will check all the wiring more closely before going to the compression test, which I had planned to do after checking all the electrical options first. I have heard the TPS can be also be suspect.

Apr 13, 2013.