No top end on the highway, help!

magnato1 · 08-03-2005, 06:10 AM

Hello everyone..
I just got my TJ about two months ago and the few times I've been on the highway I have noticed that it is very difficult to cruise at 65 on the highway, I almost always have to stay in fourth to keep it going. I wonder if this is a common issue for Jeep owners. It seems that the 4.0L should have more than enough power to keep the Jeep cruising at 65 at least. Anyways, it has 33's on it, I know that makes a difference, but still seems weird...any comments or ideas?
Thanks

Ragtop_Rob · 08-03-2005, 06:24 AM

It is true, with the aeordynamics of a brick - it can be sluggish at best at higher speeds - but my 4.0l Auto trans has no trouble holding 65 in overdrive unless I am getting into the mountians. How many miles are on it? Does it need a tune up? Are you downshifting too early?

magnato1 · 08-03-2005, 06:41 AM

It only has 42,000 miles, I bought it with 40,400. I haven't checked the plugs yet, but another thing I have noticed is that it runs stronger when it's cold, could this be an o2 sensor, or thermostat?

Paul04TJ · 08-03-2005, 06:46 AM

What gears are in it?
If someone threw 33's on with 3.07's that might explain it.

Muddman · 08-03-2005, 06:48 AM

Your gears in your axles are setup for 33s. If you would like to get back to close to factory performance you need to regear to 4.56 since it sounds like you have a 5spd.

chaoticdefekt · 08-03-2005, 06:52 AM

That's the case with my 4 cyl so your I6 should have no problem at that speed. I'd say full tune-up (since you just bought it) then regear. Contact jeep to get your stock gear ratio.

bondo303 · 08-03-2005, 07:21 AM

Looks like you and I are in the same situation. You are running 33s and most likely have 3.07 gears. 5th gear is obsolete and 4th isn't that great either. Looks like it's time for an upgrade. You need to have your gears changed to 4.56 and you will be fine. Have your checkbook ready because it is going to cost a pretty penny. Around the $1000 range.

Good Luck
-Bondo

ricky · 08-03-2005, 09:00 AM

I have 33s (10.5) though and 3.73 gearing and have no real problems keeping speed...

phildaug · 08-03-2005, 09:19 AM

I have the same issue on mine. Running 33's with 3.73 gears and auto. The Jeep fight to keep 4th on the highway between 65-75 all the time. Just one of thoes things I have learned to live with until I change gears.

bondo303 · 08-03-2005, 09:20 AM

Quote:

Originally Posted by ricky

I have 33s (10.5) though and 3.73 gearing and have no real problems keeping speed...

Do you have an Auto or Manual? There is a difference between the two. I can usually maintain 70mph but if there is an uphill, it really bogs down.

**Rocky529** · 08-03-2005, 09:32 AM

I have 32s with 3.73 gearing and I find myself downshifting to 4th on hills at about 60mph or slower. It can usually hold it's own 70 and above in 5th on hills. If you have 33s with 3.73 gearing you will definitely have to do that too... or if you have 3.07 gearing you're going to want to regear to 4.11. 100% power will be restored.

acorn · 08-03-2005, 10:50 AM

I have 3.07 gearing and 31's and I hardly use 5th gear at all. In fact I use 4th gear for anything under 70-75 because if I put it in 5th it just starts losing. At that speed I'm turning around 25K RPMs.
If you have 33's on 3.07 gearing you will have to regear or drop some tire size.

ricky · 08-03-2005, 12:01 PM

It's manual... Also, the biggest hill we have near here (FL.) is the sunshine skyway bridge... But, I haven't had any problems holding 70 mph on it... I also think the width I have helps as they aren't as heavy and have a smaller foot print... I dunno, does that make sense???

gregmondro · 08-03-2005, 12:14 PM

Quote:

Originally Posted by acorn

I have 3.07 gearing and 31's and I hardly use 5th gear at all. In fact I use 4th gear for anything under 70-75 because if I put it in 5th it just starts losing. At that speed I'm turning around 25K RPMs.
If you have 33's on 3.07 gearing you will have to regear or drop some tire size.

25k rpms? that's rotary talk! :P

jlj3394 · 08-03-2005, 12:47 PM

Quote:

Originally Posted by magnato1

Hello everyone..
I just got my TJ about two months ago and the few times I've been on the highway I have noticed that it is very difficult to cruise at 65 on the highway, I almost always have to stay in fourth to keep it going. I wonder if this is a common issue for Jeep owners. It seems that the 4.0L should have more than enough power to keep the Jeep cruising at 65 at least. Anyways, it has 33's on it, I know that makes a difference, but still seems weird...any comments or ideas?
Thanks

If you have 33's, your speedo could be off as much as 20%, depending on what size tires the Jeep shipped with. That means when it says 65, you're actually going around 78.

You can figure out how much you're off by resetting the trip odometer at a milemarker and then driving 10 or so miles (by the milemarkers) and then doing the math.

I've got 31's and it threw mine off about 10%

08-03-2005, 06:24 AM	#2
Ragtop_Rob Registered User Join Date: Jul 2005 Location: Elkridge, Maryland Posts: 125 Profile Gallery Classifieds My Jeeps	It is true, with the aeordynamics of a brick - it can be sluggish at best at higher speeds - but my 4.0l Auto trans has no trouble holding 65 in overdrive unless I am getting into the mountians. How many miles are on it? Does it need a tune up? Are you downshifting too early? __________________ 2005 Rubicon Unlimited Sahara #609 of 1000. 4 speed auto. Sirius Sat Radio, Mile Marker PE8000 Winch, 2" BB from Rocky Road, 32" BF Goodrich Radial TA/KO, RB1 NAV Radio with Ipod Controller

08-03-2005, 07:21 AM	#7
bondo303 Registered User Join Date: May 2004 Location: Long Island, NY Posts: 612 Profile Gallery Classifieds My Jeeps	Looks like you and I are in the same situation. You are running 33s and most likely have 3.07 gears. 5th gear is obsolete and 4th isn't that great either. Looks like it's time for an upgrade. You need to have your gears changed to 4.56 and you will be fine. Have your checkbook ready because it is going to cost a pretty penny. Around the $1000 range. Good Luck -Bondo __________________ 02 X Amber Fire 48 CJ2A

08-03-2005, 09:00 AM	#8
ricky Registered User Join Date: Apr 2004 Location: Florida Posts: 154 Profile Gallery Classifieds My Jeeps	I have 33s (10.5) though and 3.73 gearing and have no real problems keeping speed... __________________ '00 TJ 33 x 10.5 x 15 BFG MTS on 15 x 8 stockwheels Bunch of cool lookin' Manik stuff (black) 2" BB 1" BL BLUE JEEP CLUB MEMBER #56

08-03-2005, 09:19 AM	#9
phildaug Registered User Join Date: Jun 2005 Location: Detroit Posts: 91 Profile Gallery Classifieds My Jeeps	I have the same issue on mine. Running 33's with 3.73 gears and auto. The Jeep fight to keep 4th on the highway between 65-75 all the time. Just one of thoes things I have learned to live with until I change gears. __________________ 2004 Wranger Unlimited. Airaid Intake, TRD Throttle Body, Borla-Cat back, 3" BDS-LIFT, sitting on 33-1250 Yokohama's & MT Classic w/ RED Lock rings Pioneer Head unit with a eclipse 4-channel pushing Memphis Car Audio speakers Kenwood Sub. MY JEEP PHOTOS

08-03-2005, 10:50 AM	#12
acorn Registered User Join Date: Oct 2004 Location: Dry Valley, MO Posts: 359 Profile Gallery Classifieds My Jeeps	I have 3.07 gearing and 31's and I hardly use 5th gear at all. In fact I use 4th gear for anything under 70-75 because if I put it in 5th it just starts losing. At that speed I'm turning around 25K RPMs. If you have 33's on 3.07 gearing you will have to regear or drop some tire size. __________________ '01 TJ Sport - 5 speed 4.0 - 31X10.5 Kumho MTs and 3.07s JKS BL & BMML - JKS Quicker Disconnects Warn front bumper - Nth Oil Pan & Warn Steering Skids - Homebrew Hand Throttle Coming soon: 4.11's - OME HD Black Jeep Club #105

08-03-2005, 12:01 PM	#13
ricky Registered User Join Date: Apr 2004 Location: Florida Posts: 154 Profile Gallery Classifieds My Jeeps	It's manual... Also, the biggest hill we have near here (FL.) is the sunshine skyway bridge... But, I haven't had any problems holding 70 mph on it... I also think the width I have helps as they aren't as heavy and have a smaller foot print... I dunno, does that make sense??? __________________ '00 TJ 33 x 10.5 x 15 BFG MTS on 15 x 8 stockwheels Bunch of cool lookin' Manik stuff (black) 2" BB 1" BL BLUE JEEP CLUB MEMBER #56