Jeep Grand CherokeRPMs too high most of the time. It will go over

the 4.0L engine?
is this engine cold or hot.
why is 2000 rpm wrong for 60mph., (depends on engine and axle size and what gear you were in , then)

the idle speed for hot is too high
did you scan the PCM yet?
if hot , idle is high, is the thermostat holding water temp 180f or above. ? if not that is the problem.

driving in over drive mode actually is what gives the economy as the engine rpms will be around 300 less than direct drive . Lower rpms = fuel savings
OD should come in around 60 klm/hr and drop out at around 50 klm/hr. When you are accelerating hold the pedal in a set position and watch the rev counter (rpms ) and each gear change you will see the rpms drop and then build back up as the vehicle speed increases At 100klm/hr the revs should be around 3200 rpms or less but if over ( say 3500 rpms) then may be the OD is not coming in. One way to test a box operation is to find a speed shop with a dynomometer and test the gear selections against loads and engine rpms

My Jeep Grand Cheroke Limited 2000 did the same thing and the dealer replaced the O2 sensor and problem was solved. It about drove me crazy until it was figured out.

Take it in two steps.

Multiply 88 ft / sec by 1 mi / 5280 ft to get 88 ft*mi / 5280 ft*sec. 88 / 5280 is 1 / 60 and ft*mi / ft*sec is mi / sec so it simplifies to 1 mi / 60 sec.

Multiply 1 mi / 60 sec by 3600 sec / 1 hr to get 3600 mi*sec / 60 sec*hr. 3600 / 60 is 60 and mi*sec / sec*hr is mi / hr so it simplifies to 60 mi / hr or 60 mph.

Most low idle speed problems on these engines are due to a faulty idle air control valve but since you state the idle will go up and return to idle then i would say it is working properly i think you have a throttle body coking problem ( dirt and grit accumulates around the butterfly valve in the throttlebody ) to fix this simply remove the fresh air hose from the throttlebody and open the throttle all the way up use a clen rag and wipe clean you may use a solvent such as B12 on the rag but dont use too much

It is pretty close, but doing the math....
3900 rpms 5th gear .814 diff gear 4.3 tire rpm = 1114
stock 91 tire size is 185/60-14 circumference = 71.31 inches inches/min=79457 mi/min=1.254 mi/hr=75.23
Completely stock, 3900 rpm gives you 75 mph. not the 70 you were claiming, but you could have smaller then stock tires (one inch less of diameter gives you 72 mph at 3900).
Hope this helps, Lars

most lickely the CAT is chocked up so excessive back pressure, so clean out the cat or replace

unfortunately this is rather unpredictable. for the low cost of a battery, i would try that. if the key still is unreliable, then you know what your next step is... good luck!

I had the exact same problem on my 04 GC. I put some Techron Concentrate Plus Fuel System Cleaner in from Wal-Mart and it seemed to fix the problems right away. Let me know.

You are spinning your tires ... read your manual ... shut off the traction control .... spin away!