also what are you comparing it to? on lone pine my XJ can accelerate all the way up 70 MPH + my ZJ isn't as happy on that one. on the 2 they both do ok, unless I get shut down behind someone slow then I struggle to accelerate over 60-65

 

BCG, Considering your up in SKI country you might benifit from some higher gears in the axels, 3.73 or 4.10 would do wonders for you. Probably some 19# Mustang injectors also.

If you want more power from an XJ you can Stroke the motor, Increase intake and exhaust flow, Run High gears in the axles, get a cam, Fuel injector upgrade. Beyond that not much, without MAJOR cash being poured into the motor. These things are designed to go Slow, and arrive at the intended destination, wherever that may be.

 

Unless the underlying problem is figured out (she said it has no get up on the flat) all the aftermarket upgrades in the world are'nt going to make a difference, no disrespect, but do you guys read before you post?

 

yes its a stick
Where do you live at person that said about goin up lone pine?
And just like on highway 2 it will hardly go 55 if I slow down or let off the gas at all it wont pick up speed at all really until flat area its something new I could do 65 up that hill an like 70 even 80 one time on the freeway hehe but I havent been on the free way since its been poking seems like its since I lifted it

 

And I been thinking about getting the higher gears sometime but doesn't that cost a fortune?

 

is your cherokee stock or does it have larger tires on there? if you still have stock gears...on a stick that would be 3.07's. you could swap in an axle set from an auto cherokee, that would get you 3.55's for not too much if you shop around....(labor and parts for changing your gears is expensive).

if your xj is stock, and is sluggish as you say, i would recommend a full diagnosis. best thing you could do would be to borrow a scanner that has full data logging capabilities, that way you can look over all of your sensors, make sure everything is working properly on the engine.

 

Its got 30in tires an 4.5in lift this is it. Im thinking start with a tune up an see if that helps

 

you should not have that problem with 30" tires..... You should have the 4.0 with an AX-15 backing it turning 3.07's in the axles. I run 33" tires on my 3.07's and do many highway trips. in 5th it will cruise decent and on hill i drop it into 4th and the rmps never go above 3000 when i am in forth. if you REALLY wanted to, find an 8.25 and d30 from an auto with 3.55's-it will be alot cheaper this way. I wonder if your engine is not getting what it needs....


I would do a good tune up:
Fresh oil with bigger filter
new copper spark plugs
new spark plug wires (8mm or bigger. the biggest you can get for the money you want to spend)
new air filter
new fuel filter
new cap and rotor
take off the TB and give it a good cleaning
if you want you can do a seafoam treatment thru the brake booster and the fuel tank.


If the motor has 75XXX its a good time for a good tune up how it is.


and for getting more power remember your engine is like an equal lateral triangle:
you need air(in and out), fuel and spark and you cant just increase one with out increasing the others.

If you get a freer flowing exhaust (2.5" all the way thru) with a good intake, cold air or not(but you will notice more power with a true cold air) the computer is going adjust the fuel and the spark for you(this is where clean injectors and fuel filter come in handy and a good set of plugs and wires). once you get more air flowing thru the engine you notice more pick up and go. if you do the injector swap it will help with the new added air.

That is about all you can do just short of stroking it....


i would just start with a really good tune up. Should be in the ball park of about $100-$150 depending on local prices and what brands you get and so forth.

once you have a good tune up and you still want more power look into performance modifications.

 

Ill do the tune up soon probably I dont know if the previous owner ever did any tune ups or oil changes or anything i gotta get a oil change soon the oils real dirty but when I got it it hadnt run in 2 years so theres probably alot of crap built up in there somewhere maybe lol

 

yup first thing i would do then is before you get an oil change run 1 qt. of Tranny fluid thru the motors oil for about 200 miles before you do a full oil change.

depending on how full the oil is, you might have to remove some.

This is what the dealers use as their "engine cleaner" that they sell you for $50. It will not harm anything and all of the detergents will help clean up all of that gunk. if there is any. then again 200 miles max on the tranny fluid then do an oil change. 0w-30 if you can. It has the same properties as 10w-30 when the engine is running, but the difference is when the engine is cold it is more viscous and less "thick" than the 10w. which means the oil will lubricate better on start up and has a shorter "warm up" period to get to operating viscosity

 

We have a similar problem with our '87 comanche/5 speed. It is a renix system and yours is a HO. Our comanche is in perfect running order and it struggles to climb hills at highway speeds. It did that when it was new. it has about 87,000 miles on it. Lifting it would make the problem much worse. If it was fine before you lifted it, this could be your problem.

The higher the number, the lower the gears. 4.10 is lower than 3.07. We really want to put lower gears in the axles. It is running 3.07 now with 235/75r15 tires. It will run at about 1700rpm at 65 mph. When I press the gas pedal on the highway, nothing happens. I often need to downshift on the highway. Then it goes pretty good.

By changing to a lower gear ratio, say to 3.73, I will be running at 2095 rpm. Going lower yet, 4.10 would cause me to run at around 2300. I'm not sure I want it that low. But it may be perfect for you since you are running larger tires.

Theoretically, it will also reduce stress on the rest of your drivetrain (engine and transmission) since the gears are absorbing a lot of the stress. I believe peak torque occurs at somewhere around 2,200 rpm on these engines. With your current ratio, you may be having trouble getting your engine to that speed.

Not sure why Jeep put such high gears in these poor things.

 

I live in Wrightwood also, I think I've seen your Jeep in town. ya sounds a little off to me. even with 3.07 gears it should run stronger then that. I had 30's on my MJ, it would out run my XJ on the flats. on the hills I'd have to downshift but it would accelerate if I got into 3rd and punched it.

 

I have a 90 cherokee ( renix ) It is a auto with 31's. It would barely make it home when I got it. I did alot of maintance, open element intake, injector swap, cat back, bored TB, And now she runs real good. I have been up to wrightwood to visit sportrider And I dont have a problem making it up the hills. Also have 235000 miles on her. Injector swap made the biggest difference. Mileage went up and more power. Paid 45 bucks on ebay for injectors.

 

I put a 98 motor in my 92... its 100% stock...sept TB spacer that was on it when I got it...31's and it has just as much power as anything I have driven... and I drive alot of things.. If you jeep has no power... adding bolt on stuff to gain power is not going to help...
compression check...
full tune up...
check cat...
scan sensors for a bad ones....
exhaust leaks.....

but a good runing 4.0 in stock condition should put a smile on anyones face... they got gobs of low end tourqe and plenty of mid way power...
so dont spend money on things you dont need... get it running right first..

 

My Cherokee is running 30's with a 2 in. lift and accelerates like a bat out of hell, even up hill with 4 people inside, sounds like your engine needs some attention.

My engine is completely stock.