New to the forum. Looking for advice!

[Dumbguywith04kj]

Hi everyone! I bought a blue 04 kj limited 4wd a few weeks ago. It had 147,800 miles on it, no engine lights on, no dents, paint only fading on roof. The lights on the AC panel don't work, and one of the windows was worked on and doesn't have a roll-up limiter (or whatever) so it hits the top and makes that distinct grinding noise when the switch is pressed after that point. Also, when it is in drive, stopped on a hill, it rolls back as if it were in neutral. Every other car I had would actually keep pushing uphill slightly unless I applied brakes, so I'm concerned about that. Aside from those things, a broken wheel stud, and a faulty tpms sensor, the jeep seems fine. I bought it from a couple in Marietta GA for $3050. The girl's father bought it at 91k miles and it was driven by her until 147k.

I wanted to buy a more powerful 2003 Nissan Pathfinder, but that guy was out of town for a while and I wanted an SUV ASAP before I spent any more money on my 24 year old 242k mile Nissan Maxima. Did I get a good deal on the Jeep? Is the roll back issue normal? AC panel bulb, fuse, or wiring? I just had the last recall done, but are there any major services/repairs/failures I should expect between now and 200k miles? (I do regular synthetic oil&filter changes, and will be flushing coolant and ATF fluid here soon) What about diff fluid?

Next, I have upgrade questions since I didn't get the 240hp 265 ft/lb torque Pathfinder that I wanted. I read up on adding exhaust headers and a performance exhaust, and there is lack of clarity on the matter. First, I am aware that any HP gains would be minimal, but if I could get 10-20 hp and 10-20 ft/lbs torque, that would be neat! There are guys out there, like Scotty Kilmer, that say that increasing airflow could throw off the stock ECM and actually make things worse. Other guys claim adding performance exhaust headers results in more power/torque that was noticeable going uphill in 4th gear. Yet more claim similar results (including better MPG) from a performance exhaust. Does anyone have actual dyno results from this stuff? I suppose the issue concerns the ECM and whether or not additional steps must be taken to properly turn that new airflow into consistent power gains. I just don't want to spend $900 on wishful thinking.

This is my first time on an Internet forum, so help me learn! I look forward to hearing from you more experienced and wise members, and I hope to contribute to the forum myself as I learn and do more with my jeep. Thanks!

 

[LibertyTC]

Welcome to the forum.
The lights may need replacement in the panel, have you turned up the brightness on the turn signal stalk? Do you have an owners manual for fluid & service information /specs?
Always refer the the owners manual as the Jeep is picky regarding HOAT coolant- gear lube & transfer case specifications. The rear diff requires frequent service every 30k miles and you need to know if you have a trac-loc rear diff that needs the limited slip 4 oz bottle of friction modifier added to the rear diff gear oil.
Get your build sheet here: https://www.jeepkj.com/threads/build-sheet.64657/#post-762700
The window regulator can be repaired, but it a matter of taking off the inside door panel for a better inspection of the issue.
The 2003 factory service manual is here: http://www.colorado4wheel.com/manuals/Jeep/KJ/2003JeepKJServiceManual.pdf (no 04 available) but I do have access to one.
The Jeep is heavier than you expect 4200lbs and yea it can roll back on a steep hill, so try the parking brake & release or 2 pedal it with increase in rpm as a hill holder.
Definitely address the broken stud Asap.
As far as exhaust headers save your money. Overall the Jeep performs very well without the need for CAI or headers etc.

 

[tommudd]

Never heard of Scotty Kilmer so ???
But stock airbox with a good paper filter flows all the air you need or want, no hot air suckers are needed
performance exhaust LOL will make more noise but will not produce that much extra torque at all
headers, waste of money unless you spend a few grand on doing the whole motor with different cams, pistons having the computer done per what you did to the internals of the motor
So now back to square one aren't we ?
The KJ does well with what it has, I have 3 , 2 of them lifted bigger tires and regeared which helps a ton , best bang for the buck

I bought my 04 new off the lot, so only been playing with them 16 years now ,( wrenching for over 50 ) so maybe Scotty knows more LOL

make sure HOAT coolant only
NGK copper plugs
thermostat MOPAR only
ATF4 trans fluid
just some things to know

 

[rockymountain]

rolling back on a hill is a feature. got mine with 3K on it, now at 175K and has done it all that time, even after a new transmission.

I think the KJ has plenty grunt the way it is. Take heed, there is nothing much you can do to make it have more 'power'. If it feels slow, there may be something wrong with it. and in 4Lo you can pull down trees.

 

[jeeptorino68]

There are tuners /programmers for tgr 04+ kj though...correct?

 

[tommudd]

There are tuners /programmers for tgr 04+ kj though...correct?

Yes but they do nothing, computer will change it back. Will change shift points a bit but only thing they really do is lighten your wallet

 

[Dumbguywith04kj]

Hey guys, thanks for all the replies @LibertyTC, tommudd, and rockymountain! I just now checked the forum as I thought it sent emails to inform me of replies? Gotta check my spam to make sure.

@LibertyTC, I have turned the light dimmer to max, it affects everything but AC panel. Thanks for the link to the build sheet! I just use the brakes for hills, but I tested just letting it roll, and it rolls back and doesn't stop (as in over 35ft at my apartment lot with a ~12° incline. I have to use brakes before I roll off an embankment). So that's normal? @rockymountain

@tommudd Scotty is a famous YouTube mechanic, but his videos aren't for the KJ or even jeeps. They are mostly generic advice aimed at average consumers in general. What he says about exhaust and headers lines up with what you are saying. Like you, he actually recommends against it without doing all the other stuff, as you said.

For me it's just perfectionism. The power is fine I just hate that the Jeep's 3.7 is outperformed by engines of lesser displacement. The only thing I feel may be actually be wrong besides the door locking system (recently discovered) is the fuel economy. I plan to do an actual test, but my jeep drinks fuel and I had a Tundra (RIP) that drank less.

 

[rockymountain]

Hey guys, thanks for all the replies @LibertyTC, tommudd, and rockymountain! I just now checked the forum as I thought it sent emails to inform me of replies? Gotta check my spam to make sure.

I just use the brakes for hills, but I tested just letting it roll, and it rolls back and doesn't stop (as in over 35ft at my apartment lot with a ~12° incline. I have to use brakes before I roll off an embankment). So that's normal? [USER=6129]@rockymountain
[/USER]

yep. If you want hill assist feature you can spring for a JK.

you should get around 18 Mpg is all is normal.

 

[tommudd]

As far as gas mileage there are many variables
As far as my driving style most call it aggressive , I hit the rev limiter at least once daily just leaving my place and its on a old country road LOL
Getting on interstate, most time its 75-80 before I hit the main road
My 04 lifted 4.5 inches, 32s, 4.10 gearing, with lots of extra weight ( front and rear aftermarket bumpers, heavy steel skids, rock rails and tools averaged 21-22 on interstate at 75 plus easy, have gotten over 23 going across Pa, over to do some work with Marlin at JBA
My 03 lifted 2.5 inches , 4.10s, 31s does about 20 on the highway and no slack its my daily ad hits 80-85 daily going to work ( drive almost 50 miles one way )
The 05 mainly stock except for OME coils etc gets the worst of any of them 19 or so LOL
But change plugs in them all every 25-30,000 miles, oil changes every 3-3500, diffs, transfer case every 7-8000, transmissions every 45-50,000, airfilters every 3 months or so . So I keep up on regular maintenance on all of them which I think is key and keeping everything lubed well , plus do not be afraid to run them.

 

[rockymountain]

I get 17 city, should’ve clarified. I get 22 hway.
These kjs should’ve all come with 4.10s. Proof is here on this site time and time again.

i would love to have any of your kjs @tommudd

 

[LibertyTC]

Also all KJ's should have come with 25 Gallon fuel tanks as well !
I wish mine had 4:10's it needs it! (donations gladly accepted )

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[uss2defiant]

13-14mpg according to the EVIC but it's a weekend warrior now.

 

[tommudd]

Also all KJ's should have come with 25 Gallon fuel tanks as well !
I wish mine had 4:10's it needs it! (donations gladly accepted )

You must be registered for see images attach

4.10 equipped KJs are still out there !
just located another 4 cylinder with only 53,000 miles on it, was wrecked back in 2016 and been in a garage jacked up on jack stands ever since.
Father passed away and kids ( all in their late 20s/early 30s ) want that junk removed LOL
This weekend going to go look it over ( if I don't get stopped for being out cruising ) ha ha

 

[Dumbguywith04kj]

Hm, I will update you guys once I fill my gas tank filled again and get a rough mpg estimate. Any of you guys in GA or upstate SC? I'd like to buy a set of used 05 limited 17" wheels, or used aftermarket ones. Yeah they're more expensive to put tires on, but they look better IMO.

 

[Brendon Holt]

For some MPG data I average about 16MPG mixed in town and highway. If I drive all highway I can MAYBE pull 18-19MPG All stock 2002 KJ 4x4. Does have the LSD and all the off-road package stuff but Idk if that makes a difference. Also has some 245/70/16 tires. I think the 2002s get the worst mileage from the ratings I've seen but I could be wrong.