i'm working with a 94 grand cherokee laredo 5.2. it's all stock and just has over 140k on it. i'm looking to personalize it a little, but wasn't sure what not to do to make the gas mileage even lower seeing how i'm currently sitting at 11.5-12 around town.
i don't know if i'll be taking it off road anytime soon, and if i do, it won't be anything hardcore at all since it's my every day vehicle and it needs to last. i'm thinking about getting 1-2'' spacers to make it slightly more aggressive and switching out the stock wheels for some sort of steel wheel. will doing either of this necessarily change the way it handles or performs? i wasn't sure if the steel wheels alone would add a noticeable amount of weight.
I should have mentioned cleaning the throttle body and IAC also . You'll see if it needs attention while checking the plenum gasket . Look for oil slicked over the bottom , and pooling possibly in the rear corners . A certain amount of blow by via the PCV is normal but if shiny wet , you got a bad vacuum leak drawing oil into the intake .
dont feel bad, i get about 13 on the highway but then again im lifted with a roof rack with full size spare up top and some not too fuel efficient mt's. not exactly aerodynamic... great jeep to start with in my opinion though!
ZJ's aren't the most fuel efficient vehicles out there, if ya know what I mean. Hmmmm? I wonder if Toyota could make a Prius with OR capabilities that could haul a ****e load of people and supplies into the wilderness? I'd buy one. Okay, maybe not.
My ZJ has traction control, I call it my right foot.....
Don't forget the O2 sensor too while replacing the cat and muffler!!.
When i replaced all of the above i had a 1 to 2 mpg increase.
Make certain you get the NTK or Mopar equivalent O2 sensor and avoid Bosch like the plague!!!
Anything you do that sticks the ZJ up higher in the air, or make it turn larger tires, will lower your MPG to some degree. Good tune up as mentioned above, plenum gasket repair, and upstream O2 sensor will get you about all the MPG you're going to get out of one of these. If you can make your 5.2 run consistently over 14 MPG with mostly city driving, give yourself a pat on the back and write a book about it. I'll buy one.
Welcome to the forum and the addiction man lol. If you want to maximize fuel economy, stay away from lifts and bigger tires. I was averaging between 14.5 and 16ish mpg with my 5.2 before the lift, now the best I've seen is 13.8 with the 33's. Pre and post lift numbers were all hand calculated as my overhead reads 15.8 even with the mudders.
98 ZJ Limited- NP231 swap, IRO 4.5 inch Springs, Hydro Shocks, IRO adjustable double shear track bar, JKS quick discos 33x12.50 Kumho Road Venture MT on 15x8 D windows with 3.75 inch BS
My build thread- [url]http://www.jeepforum.com/forum/f197/98zjltds-build-thread-1557637/[/url]