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Discussion Starter #1
ok this is strange, 2001 Jeep wrangler 2.5 automatic.
I don't usually go over the speed limit, when we lived in Va it was 55 max so since I never got on the interstate with it I never even got over 50, NOW living down in NC some of the roads are so long I might go a little over now and then, like everybody else including the st boys that pass me, now hears the problem, the Jeep will not go over 64 mph. I know its a replacement 2.5 but the trans has a new filter and to the best of my knowledge is ain't slipping, I cant feel it anyway, brand new tune up wires cap rotor plugs, plugs are at .035, fuel pump was replaced 5 years ago tires have 35 in em, the only thing that's different from stock is the tires are 235 instead of 205, why is it only going 64? there is a rattling sound from the front when you start it , but it goes away when you give it gas, I'm thinking that is a slightly stretched timing chain cause once I hauled about 2500 lbs of wood and its made that noise ever since.
Oh and its only getting about 16 miles to a gallon
any ideas will help guys, this is driving me nuts.
 

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Discussion Starter #7
Tires are 235 75 R 15's BFG At ko's
Front diff is a stock dana 30, rear is a stock dana 35C trans is a stock 3 speed with automatic overdrive not sure of the gears, been a long time since I looked that up, I think the diffs are 2 something cause all the 4L guys want em LOL
 

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Had a 2000 with the 4cyl and a 5 speed. All stock and went to a 31 inch tire and it would barely hit 55. I would suggest regearing or a LS swap.... I'd personally go with the LS
 

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Discussion Starter #9
when you say LS, I hope you mean limited slip diffs not swapping to a LS engine.either way I really don't want limited slip diffs, don't need em, I have front calipers from a car that used the rear brake pas as the parking brake and a cable going to the front like the one that goes to the rear, I simply pull up 3 or 4 clicks and all 4 now have traction, but the whole no over 64 mph is driving me nuts, not that anything around here locally is above 55 except 95 and I ain't drivin 95, but I wanna know what the hell is going on
 

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Discussion Starter #12
How many miles on the Jeep? How are the cats and O2 sensors?
cat is clean and clear I took it off and was gonna guut it but useing a low power flashlight you can see right through it just lek a boiler with brand new tubes, the 1 o2 sensor if also fine

That number specifically is tire width in millimetres. Wolfen is running a 235 75r15 which is 27" in diameter. Effectively stock and shouldn't require a regear.
Thank you anything under 30 requires no regear
I looked at the car the fire pattern is at the beginning of the terminal could it be the chain?
 

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cat is clean and clear I took it off and was gonna guut it but useing a low power flashlight you can see right through it just lek a boiler with brand new tubes, the 1 o2 sensor if also fine

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I looked at the car the fire pattern is at the beginning of the terminal could it be the chain?
How many miles? My cats and sensors looked clean and fine at 110k miles, but I did notice an improvement after all were replaced. They allegedly only last 90-100k miles. Rule out the more common stuff before going to the timing chain.
 

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Have you checked the fuel filter?
Fuel filters in TJs are considered lifetime filters since they have such a large surface area.
 

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Find a set of cheap 205's. From a scrap yard or something. Put them on and see if it makes a difference. My bet is it will. When I went from 225/75-265/75 I noticed a huge difference in how my 05 2.4 with 3.73's was running. Way slower and I had to shift at different points. It basically made 6th gear obsolete for me and threw my speedo way outta wack. I need to use a gps speedo now.
 

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207 is 27" dia, 235 is 29". Both are "stock" size, but the difference would be enough to show on your speedometer. Can also through off your MPG calculation, even so 16 MPG is not bad.

As above verify speed with a GPS, find out axle gearing. Agree that regearing should not be needed, it's good to know what you are working with.
 

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when you say LS, I hope you mean limited slip diffs not swapping to a LS engine.
LS engine, then you can go as fast as you want.
But seriously I think it's just a 2.5 thing. Mine was fine around town and on the trail but on the highway it was a turd. Not saying you can't do 70 without regearing, but my 4.0 with 4.56 gears struggles to hit 70 with 35s.
 
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