I have a 99 cherokee sport, i went on vacation for a week, came back and it ran like crap. it mis fires and sort of "chugs" at cruising speed. and idles rough and rather terribly. i thought maybe the injectors were bad because the code i get is p0202 which says injector 2 circuit open. recently i discovered if i pull a vacum line off the intake it smooths out and runs pretty good. anyone have any ideas??

 

Possible causes are; defective ASD relay,defective injector,defective PCM, or defective connectors or wiring. if you have a set of noid lights check for injector pulse signal. if you have it replace the injector.