SanDiegoXJ
NAXJA Forum User
- Location
- San Diego, CA
Ok, let me begin by saying I've done several searches on this and haven't yet been able to simulate my problem. I have already changed cap, rotor, plugs, IAC, TPS, and cleaned the intake with seafoam. I've done a search for vacuum leaks with carb cleaner to no avail. Here's the dilemma...
I have a 1994 Jeep Cherokee Country with a 4.0L HO engine and AW4 tranny. ATM, there are no mods to the Jeep other than the aforementioned replacement parts. Everything else is OEM....and I believe it to be original equipment, though I'm the third owner and no service records. When cold, the Jeep runs fantastic. When it warms up, the idle begins to run a little rough but nothing too undesireable. My problem really seems to be isolated to something I just haven't figured out yet.
When driving at freeway speeds the Jeep seems to hesitate or cut out like its starving for fuel. It only happens briefly then resumes normal driving. Sometimes the issue becomes repetetive, but ultimately I can step on the gas or the breaks and the issue goes away. I've tried warming it up and running it high rev in the driveway, of course, the issue never reappears to even begin to diagnose where it's coming from.
But here's the other kicker....it seems to happen only when I go over a bump. Not a big bump mind you, just an unevenness in the freeway or even crossing the lane dividers often causes it.
It also seems that occasionally, at idle, the rpm's will drop near stalling, recoup and continue to pur. The engine doesn't shake violently or sputter. There's no backfiring. The hesitation does not occur under acceleration or deceleration. I replaced the IAC and and TPS last. Consequently when I checked the error codes I got codes 34 and 24, which, if I'm reading correctly means incorrect voltage at TPS and IAC....just now cleared the codes again to see if they reappear, but after idling for 15min... no codes yet.
Anywho, any suggestions or advice you guys got would be sincerly appreciated....this is really starting to irk me. I just don't want whatever is going bad to finally go bad when I'm out in BFE.
Thanx heaps!
Michael
I have a 1994 Jeep Cherokee Country with a 4.0L HO engine and AW4 tranny. ATM, there are no mods to the Jeep other than the aforementioned replacement parts. Everything else is OEM....and I believe it to be original equipment, though I'm the third owner and no service records. When cold, the Jeep runs fantastic. When it warms up, the idle begins to run a little rough but nothing too undesireable. My problem really seems to be isolated to something I just haven't figured out yet.
When driving at freeway speeds the Jeep seems to hesitate or cut out like its starving for fuel. It only happens briefly then resumes normal driving. Sometimes the issue becomes repetetive, but ultimately I can step on the gas or the breaks and the issue goes away. I've tried warming it up and running it high rev in the driveway, of course, the issue never reappears to even begin to diagnose where it's coming from.
But here's the other kicker....it seems to happen only when I go over a bump. Not a big bump mind you, just an unevenness in the freeway or even crossing the lane dividers often causes it.
It also seems that occasionally, at idle, the rpm's will drop near stalling, recoup and continue to pur. The engine doesn't shake violently or sputter. There's no backfiring. The hesitation does not occur under acceleration or deceleration. I replaced the IAC and and TPS last. Consequently when I checked the error codes I got codes 34 and 24, which, if I'm reading correctly means incorrect voltage at TPS and IAC....just now cleared the codes again to see if they reappear, but after idling for 15min... no codes yet.
Anywho, any suggestions or advice you guys got would be sincerly appreciated....this is really starting to irk me. I just don't want whatever is going bad to finally go bad when I'm out in BFE.
Thanx heaps!
Michael