Mike Fitz

Hey everyone!

Wife and I just sold my XJ and bought a 2007 JKU. We are super excited!
We only have 31's right now, and just a Mammoth leveling kit.

A few questions that I could find an exact answer to:

Acceleration - I feel like the gas pedal is not very responsive. Is this normal? Say from start, or on highway, if I step on it to get going, I can depress the pedal pretty far down before the Jeep (its an automatic) downshifts and accelerates. If I press pedal down slowly I can depress it more than halfway before I feel the Jeep get moving. Otherwise the Jeeps seems to run well and no issues that I can find. Maybe it's just the fact that its heavier than my XJ was.

Steering - The steering wheel seems "loose" and I feel like Im all over my lane. It seems to be working correctly, but its almost like the power steering is working "too well" which sounds dumb but the only way I can think to explain it. I also read some stuff on here about the subtle "click" if I move the wheel back and forth, I can feel in steering wheel and pedal when this happens. Usually at slower speeds. Not sure if that's related.

Thank you for your thoughts!

rob_engineer

If the tires are not stock diameter then maybe nobody ever reprogrammed the computer which would throw off the shift points.

EHarris

This above for sure. Definitely get a superchips. They are used for sale all the time. Makes a difference in my opinion.

Steering could be the intermediate steering shaft which is 2 bolts and $150. Ball joints are usually an issue too.

muddbutt

I have 33's on my stock 11 rubicon. It's definatly looser in the steering. The 3.8 motor is sluggish in the bottom end. I have a traildash (pricey 500$) that I can tune it with. I bought the traildash because I have have problems seeing the red needle on the dash (color blind) It kinda blends in I guess. I use the traildash for all things like speedometer and fuel percentage left. With the traildash/rubicon I can also do things like lock the front axles only. With that said I do tune the jeep with it. I added the 89 octane tune ( you can tune for 92 but it pings like hell if you use cheap gas) I set my tire size to correct the speedometer. I have a six speed manual so I can get around the sluggishness by running high rpms. Its a jeep not a race car so I don't mind. The Rubicon has a gear ratio of 4:10. You can regear to get more snap. I think the non-rubicon models have 3.73 or 3.21. Also keep an eye on the oil level. 3.8's use oil if you bog them down.

karls10jk

Coming from a handful of TJ's, I felt your pain on the pedal. I chalked it up to electronic throttle and went with the Superchips which has taken a lot of the lag out of the pedal. I would guess that it's in the "tunes" they offer. Outside of ditching the lag, I haven't felt a noticeable difference with the Superchips, still recommend it though for that throttle lag. 31's shouldn't be an issue for the Jeep, it was also the first thing I did (again, coming from the TJ/ XJ generation where lift was required for larger tires).

Finding out your gear ratio would be the next step I'd take. If you've got 3.21 then it's not going to be fast ever. The 3.73 should be decent, I know I enjoy mine.....even with 35's and lots of weight.

Mike Fitz

Thank you all for your responses. Sheds some light in the subject.

Just found my build sheet online, states it’s the 4.1 gear ratio. I’ll do some more digging.

I’ll post back if I find anything conclusive!

nthinuf

Yep, 4.10's were available on non-rubicons in 07, (hasn't been an option any other year). You got lucky with that ratio.

E-lockers were another non-rubicon option available that year, do you have a locker button on that lower dash panel?

For the steering: as the lift height increases, the caster decreases, and the steering gets progressively flightier. At 2", many people won't bother to correct it. Others do. If you choose to do so, your options are Cam Bolts, a set of control arm Brackets, a set of Fixed control arms (longer lowers or shorter uppers), or a set of adjustable control arms (either upper or lower). There are pro's and con's, so do a little reading and decide which is right for you.

Have you had an alignment done? If so, post the printout so we know where you're at. Some shops will print out the current specs for free, so that might be an option.

And as noted, it could be another component like bj's or rod ends or even improper torque on bolts.

Acceleration: the 3.8 and the particular auto trans in those years is a bad combination from a performance perspective. But as noted, there are ways to take some of the lag out of the gas pedal, if you think they are worth the price tag. The offerings from Superchips may help, as noted, and the Pedal Commander is another one to read about. (the sales blurb states that it : "Eliminates Drive-By-Wire Pedal Delay" and "Improves vehicle acceleration".)

Mike Fitz

I appreciate all of your input.
Now I have other more pressing issues.
I’m concerned I bought from the wrong dealership.

Yesterday I had AC on for a bit, now whenever I turn right, cups of water pour onto the passenger floor from somewhere behind the glove box.

I’m also getting an intermittent “red lightning bolt” light on dash. Happened 3 separate times, several minutes into a drive. no noticeable differences, no code being shown. Last night light came on as I started, and it was blinking, and the traction control light came in too (I had just redone rear brakes) and it barely started, hesitation, sounded rough like it wanted to stall. I shut it off, started again, no issue.

Dinky Dau

If it is like most vehicles the rubber drain line for condensation has come off the evaporator underneath the dash.

Mike Fitz

I was trying to find the drain line on the firewall earlier. Not sure I could find it. I saw something on driver side in engine bay that looked to be a small back hose, but it looked like it was pushed into the firewall, if that makes sense, with no hose line sticking out.
I have no idea how that would have happened though...