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 lower O2 with the upstream on order and installing soon (was pretty nasty). Also have a MAP sensor just installed as well. Replaced the dreaded CPS and still no major improvement. The valve cover gasket looks like it needs to be replaced. 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. I’ve done some slight adjustments to tps but it really only either cranks rpms up to 2500-3000 rpms at idle until I kill it, comes close to killing it or has it idle like usual. Any ideas on would be greatly appreciated. I’ve done a lot of research but so far efforts have not seen any real results. PO installed tps so maybe I needs to be correctly adjusted with multi meter?
1988 Jeep Cherokee 4.0