Recently bought an 88' Cherokee XJ with a 4.0. When I went to go see it wouldn't start. But after unplugging and re connecting the CPS it ran but really roughly. Idles low at around 200-300 rpms. Replaced the tps, cleaned throttle body and IAC, replaced O2. Also have a MAP sensor just installed as well. Replaced the dreaded CPS and still no major improvement. The valvle cover gasket looks like it needs to be replaced. Repaired replaced some vacuum lines that needed it but haven't found to many issues with that. When I rev it up then let off the gas it usually kills it but will start back up and continue to idle roughly. Also replaced fuel filter. The TPS has been properly adjusted to 17 percent of the base reading from the multi meter. Any ideas on would be greatly appreciated. I've done a lot of research but so far efforts have not seen any real results. Just looked at the C101 connector and it was terribly tarred and nasty on the inside. Is that a possible cause for it to idle poorly? Haven't got to cleaning t yet as I'm out of cleaner at the moment. Any input would greatly be appreciated!

 

Injectors? Is it missing? might as well rule out a fuel pump by doing the poor mans prime.

 

Make sure your intake manifold bolts are snug. Did you clean your throttle body and IAC before adjusting the TPS?