so here i'am again.. posting another thread on my jeep(lifted 4 1/2 inches runnin 33" tires). it still wont go over 45 and now she idle's and such. replaced the computer,changed the fuel filter, yada yada yada. the shop says the engine is totally fine and she shifts just fine.... Now i read on a thread here that if im running my lift/tires i shoulda changed out the stock gearing in order to get my power back?? should i go with that or do you guys think it might be something else? btw i have no sye or anything else done to it besides the drop...i think?

 

Because I cannot tell from your info,I assume your 91 is the xj with the auto trans and 33s,if so 4.56 gears would be my choice,if it is a manual,4.10s,your stock gears are causing a loss of power,but even with that you should be able to go over 45 with stock gears,just takes a bit longer to get there.

 

I totally agree !! I have 6" lift and run 32's open with 3.55's and have no problen doing 65-70 . If you've checked everything else you might want to look at the exhaust system for restrictions. you should be able to do normal speeds without a gear change. keep lookin' you'll get it !!!

 

45 is more like 55 if you did not change the speedo gear

go with the 4.56 gears

 

yes its an auto. well she wont do over 45 Period unless im going down hill.. she definitely feels like something is restricting it like no other.. could it be the exaust causing it to not wanna go over 45? its not stock.. i think its a bank power exhaust system?

 

Sounds like the converter is clogged in the exhaust

 

that is defiantly a good possibility

 

how would i go about un-clogging it? cut it off, blow, re-weld?...

 

Get a new one.

 

easier said than done... But thanks guys im gonna look into a new exhaust just incase.

 

x2 on the exhaust restriction. i posted here today with no replies.

why does a 00" 4.0l need 3 cat. converters for?
is there a way to eliminate any of them. i'm sure i can delete the one at the muff. since theres no o2 sensor in that one, but any mods availible for one of the other two.

 

I have never heard of an xj with 3 cats,are you 100% sure they are all cats?can you take a picture? it would be interesting to see.

 

sure will. there is 2 at the manifold/ downpipe area, both with o2 sensors, and then one just infront of the muff.

 

x2 interesting indeed.

 

yes, cut it off then get a rod or pipe that will fit in it. now get a hammer and beat the ceramic out of it. once it is all out just re-weld it. really easy. and it sounds a lot better. mine was plugged, not as bad but i noticed a huge improvement after i did this. the only reason i gutted it was because i couldnt afford a new one at the time. buy a new one when you can.