Tranny Touble

Hello all. It seems like i might have some bad news. I have an 89 Jeep Comanche with the 4.0. I had some rough times recently getting her running. I finally got her running (replaced everything cept the TPS) but now i think it might be acting up. I put in new fuel pump. Now i have a high idle. Never had one before it always idled about 600 rpms now its about 2000. This cant be good. And sometimes when i first start it it wants to miss and kinda backfire. Plus i have noticed it seems like i have NO power whatsoever. PLus i think that OD is slipping. (automatic) It used to run about 2k doin 65 on the highway. Now if im on a flat hill its about 2500 rpms and if i have to go up a hill or give it more gas it goes up to 3000 rpms. I just thought it wasnt goin into OD but i pulled it down into third and it downshifted so it was in OD. I know this tranny is computer controlled and it didnt do this two weeks ago and i havent driven it more than 20 miles. The only thing that i have done to it that is tranny related is i accidently broke the kick down (to kick it down a gear or two when i give her hell) and i dont think this could do anything, all i have noticed is that it wont downshift when i push on the gas hard. So im wondering if there is anything cept a tranny that is going out that could cause it to slip in OD? the fluid is fine and most of it is fairly new(blew a hose and had to replace 3 quarts) so im at a loss
Brandon

I am assuming you have the AW4 transmission, if not this advice is all wrong. :}

You need to replace or fix the tranny cable. It's not a kickdown cable as in hydraulic controlled trannies, but rather it controls the internal hydraulic pressure which affect the shift firmness. Having this broken will make it shift like crap and possible cause the torque converter to not lockup (your higher rpm problem).

You mentioned that you have not replaced the TPS. That's the next suspect for your problems as the trans computer uses that signal to determine when to downshift. No TPS signal means it won't downshift when you hit the gas and will upshift very quickly. Upshifting very quick will certainly make your engine seem gutless. Or vice-versa. On the 89 the TPS has two outputs with one going to the engine computer and the other to the trans computer under the right hand side of the dash.

Your increased rpm's and "slipping" in 4th gear sounds like the torque converter is not locking up. There is a switch on the brake pedal for the trans computer that signals the computer to unlock the torque converter when you apply the brakes. If it's gummed up or stuck, the torque converter may not lock. The usual test for this is to drive along normally at highway speed and tap the brake with your left foot and the rpm should jump a few hundred rpm as the converter unlocks.