1988, 4L, 5 speed, 1990 ECU for manual, REM II reader, all Crusier's tips completed minus C101 delete, all stock otherwise.
I hope not to be to long on this but after 3 years of it bothering me it is fixed. Jeep always ran great and all readings on sensors always read as they should (except for the one I neglected to look at). The problem was when I would be pulling onto a highway and bringing it up to speed when I hit 3rd gear and if I put it into WOT open loop I would always get a little skipping hesitation almost like a slight misfire (the rig is still running 3.07 gears on 31's so this happened at 55mph and 2800RPM). It was never a problem more of and annoyance, I knew it happened and could replicate on demand, but I didn't really have to run it out to WOT open loop to come to speed.
I went on our camping trip last week, hauled the 4x10 trailer with normal gear and canoes as always, no problems on the way there. On the way home the one town had severe tidal flooding (maybe 3/4 of the 31's deep, I've definitely been deeper no problems). Once I get on open highway 4th gear 2000ish RPM cruising BANG yellow light on REM II lights and stays lit (NEVER does that), Knock Sensor Fault (per REM II) as soon as I push in the clutch light goes off. I put one of the readings to Knock sensor no constant reading it would flicker 1 or 2 sometimes, but I could get the light to come on consistently by cruising in any gear holding 2000ish RPM's. When I got home and all put away I dug in my pick and pull misc box and pulled a knock sensor and threw her in. 3 days and 300mi later I can say that the reader shows expected Knock swing and 3rd gear hesitation no longer exists. I know that the knock sensor is not that crucial for the actual running of the 4L beyond retarding or advancing ignition time, hence why I never looked at its reading on the REM II (who knows how long it was on the fritz).
It may or may not be what fixed the problem that I was having but I just wanted to put the experience I was having and what seemed to fix it out there for any fellow RENIX owners that maybe experiencing a similar situtaion.
I hope not to be to long on this but after 3 years of it bothering me it is fixed. Jeep always ran great and all readings on sensors always read as they should (except for the one I neglected to look at). The problem was when I would be pulling onto a highway and bringing it up to speed when I hit 3rd gear and if I put it into WOT open loop I would always get a little skipping hesitation almost like a slight misfire (the rig is still running 3.07 gears on 31's so this happened at 55mph and 2800RPM). It was never a problem more of and annoyance, I knew it happened and could replicate on demand, but I didn't really have to run it out to WOT open loop to come to speed.
I went on our camping trip last week, hauled the 4x10 trailer with normal gear and canoes as always, no problems on the way there. On the way home the one town had severe tidal flooding (maybe 3/4 of the 31's deep, I've definitely been deeper no problems). Once I get on open highway 4th gear 2000ish RPM cruising BANG yellow light on REM II lights and stays lit (NEVER does that), Knock Sensor Fault (per REM II) as soon as I push in the clutch light goes off. I put one of the readings to Knock sensor no constant reading it would flicker 1 or 2 sometimes, but I could get the light to come on consistently by cruising in any gear holding 2000ish RPM's. When I got home and all put away I dug in my pick and pull misc box and pulled a knock sensor and threw her in. 3 days and 300mi later I can say that the reader shows expected Knock swing and 3rd gear hesitation no longer exists. I know that the knock sensor is not that crucial for the actual running of the 4L beyond retarding or advancing ignition time, hence why I never looked at its reading on the REM II (who knows how long it was on the fritz).
It may or may not be what fixed the problem that I was having but I just wanted to put the experience I was having and what seemed to fix it out there for any fellow RENIX owners that maybe experiencing a similar situtaion.
I believe Your knock sensor was failing. It caused the slight hesitation at WOT. Replacing it fixed the issue.