Been playing with the wifes 1990 XJ for a few months now (4.0 auto fuel inj ) and it has an interesting stalling problem. If you drive it light on the gas ( and I mean light, as in being stuck in a traffic jam and resting your foot on the gas pedal to creep ahead) and you let off it will stall out and die. Always starts up right after, rarely with a high idle afterwards ( although occasionally, will run up to 3000 rpm for about 3 or 4 seconds then returns to norm)
Now if you throw it in Neutral when its sputtering it will go right back to a decent idle without having to press the gas pedal. At first I thought it may just be plugs wires cap etc... your usual tune up, but the problem persisted. I changed the TPS and IAC sensors ( twice each, even though both tested out fine) Ive cleaned the throttle body, vaccuum tested the lines , no leaks, tested MAP , MAT sensors, O2 sensor, changed filters, fuel injectors, checked fuel pressure. Even cleaned and rebuilt the NSS. ABout the only thing I havent changed is the CPS because it seemed to me this was a fuel/Air problem. That being said, Im not sure whats going on anymore. Idle is steady ( as steady as a renix can be anyhow ) Ive checked the bolts for the torque convertor to be sure they havent backed off any.... Needless to say I will be changing out the CPS shortly ( was avoiding it because its such a PIA to get to) but Im wondering if anyone else has any ideas as to what it could be? Makes no difference if you are in 4 wheel or 2, only happens in first or reverse, you can be as light on the gas as you want in Neutral and its fine. No backfiring or smoke (black or white), fluid levels all good.... Anyone? Thanks in advance for any help on what to try next.......
Now if you throw it in Neutral when its sputtering it will go right back to a decent idle without having to press the gas pedal. At first I thought it may just be plugs wires cap etc... your usual tune up, but the problem persisted. I changed the TPS and IAC sensors ( twice each, even though both tested out fine) Ive cleaned the throttle body, vaccuum tested the lines , no leaks, tested MAP , MAT sensors, O2 sensor, changed filters, fuel injectors, checked fuel pressure. Even cleaned and rebuilt the NSS. ABout the only thing I havent changed is the CPS because it seemed to me this was a fuel/Air problem. That being said, Im not sure whats going on anymore. Idle is steady ( as steady as a renix can be anyhow ) Ive checked the bolts for the torque convertor to be sure they havent backed off any.... Needless to say I will be changing out the CPS shortly ( was avoiding it because its such a PIA to get to) but Im wondering if anyone else has any ideas as to what it could be? Makes no difference if you are in 4 wheel or 2, only happens in first or reverse, you can be as light on the gas as you want in Neutral and its fine. No backfiring or smoke (black or white), fluid levels all good.... Anyone? Thanks in advance for any help on what to try next.......
