smokey_doge

I have a stock 1995 Jeep Cherokee 4.0, 2WD. It's always been like this since I've had it, which has been around 5 months. At around 60-65 mph, the RPMs are pushing 3-3.2k. This seems pretty high to me. I just put 12-hole injectors on it, however, this was happening before. For reference over the time I've had it I've installed a new IAC, went through the whole ignition system, new water pump, new o2 sensor, new fan clutch, new electric fan for the radiator or whatever it goes to, and cleaned out the throttle body. It starts at 1500rpms but quickly idles down to around 800. It idles smoothly. Could be a totally different issue as I just noticed this after swapping the injectors, but the RPMs also bounce around slightly when I left off the gas at around 35-45mph. Never have any trouble starting it, always starts in like half a second. It seems to drive pretty well, but I feel like those high rpms are really hurting my fuel economy, and I don't think it's necessarily normal. I've read it may possibly be the torque converter, but I'd like to know a bit more. Any help would be greatly appreciated. (~220,000 miles for anyone wondering)

IJM

When you accelerate up through the gears to about 65 or so, you should hear it shift into 2nd, then 3rd, then 4th, and finally you'll feel the torque converter lock up in 4th. Does this happen?

smokey_doge

I feel 3 shifts, which I understand are 1-2, 2-3, and 3-4. I'm not sure I'm feeling the torque converter locking up. What should it feel like?

Sig220

It should have felt like those 3 shifts you mentioned. From a complete stop with easy acceleration, you should feel 1-2, 2-3, 3-4 and at about 45-50mph you should feel the torque converter lock up (4-OD) and a drop in rpms. This is with stock diameter tires, bigger tires the final lock up would change. If it doesn't lock up, you should be getting a "check engine" light which should be a P740 code.

smokey_doge

I don't think I'm feeling it lock up. I have no check engine light. Its a 95, pre OBD2 if that's any help, but I see no drop in rpms after 4th.

00t444e

If you put it in 3rd going those speeds does anything change?

exasemech

OK here's some data.
my 2000xj 4.0,stock gears, 242 , stock tire size.
this am at 60 mph in D tach showed about 2000 rpm with.TC not locked, dropped a couple hundred with it locked. At 60 in "3" could get to about 3000 rpm with tc. locked.

I think you are in 3, not D (4th) for whatever reason.
Note this was on a level road and not accelerating, if you were in D and gave it some throttle it of course downshifts to 3 and you're back to 3 k.
I found no way to get anywhere near 3 k when it was actually in D(4th)

IJM

When you're cruising along at 60 plus and just barely tap the brakes with no change in throttle input, do the revs rise a bit or stay the same?