Does anyone know the best spark plugs for mpg on a 96 sport 4.0l

 

Nothing fancy. Just plain copper ones. You can check the sticker under the hood (RC12LYC ?). Or NGK's. I'm running NGK ZFR5N's in my '96.

 

Despite what everyone said I got E3 plugs a couple of years ago and they have treated me fine for roughly 1,000 miles, no crazy improvement or issues. I do have a set of champion coppers in case they did ever give me problems. I'd stick with cheap coppers.

 

I put Bosch Platinum's in my '96 in place of the original Champions that were still in it when I got it. 98K on them. Ran fine but only 13mpg. Anyways I didn't notice any improvement with the Bosch except of course for MUCH IMPROVED mpg. They didn't last any longer than a copper plug would have though. I was advised here that a premium plug just isn't needed for these motors.

 

And I don't doubt it. I don't remember what plugs mine had it in when I pulled them out at 138k.

 

I can't believe how good mine ran when I first got it after pulling the plugs. The electrodes were down to the insulator tips. Probably could have used a flat tip screwdriver as a feeler gauge. I will say these XJ's having a very good ignition system.

 

yeah I did the same thing when i first got mine i didn’t really know much with it being my first vehicle and I just went on Amazon and clicked on the first one and it said it would fit and I put them in and I’m just now realizing now that I know more about cars that there not the best plugs so now I’m trying to get the right ones

 

There was a thread that ran on here actively for several years. All about improving mileage. The OP was determined to get 25mpg. After hundreds (thousands?) of posts on the subject, at the end, he was getting the same mileage as I was with a stock Cherokee.

So, there ya go. Put the coppers in and be happy. Your driving habits will make far more difference than any expensive "upgrade" part or gimmick you can throw at it.

It's a really nice vehicle with the aerodynamics of a brick and an old-school engine. It is what it is.

 

"an old-school engine"
GLAD you didn't use the "T" word!

 

Milage CAN be improved in the Cherokee XJ. It takes some work and some money. Some of it is stuff we could be doing just keeping ours runing. Charley3 on another forum tested one mod at a time on his XJ until he upped it to 24 mpg freeway. Pretty good for an auto transmission XJ with mild lift, skid plates and slightly bigger tires.

Charley3 thread. https://www.jeepforum.com/forum/f11/my-goal-get-25-mpg-my-99-xj-30-x-9-5-r15-ats-1551782/#/topics/1551782

 

Big deal. That was the same result that our intrepid mileage warrior finally got, which matched my stock XJ. Tune it up, keep your tires inflated, and stop tailgating.

 

C'mon, Earl, you should know I know better!

 

Yup, a 20+ year old brick. It's all about smiles per gallon

 

When looking at his before and after numbers it is kind of a deal. Maybe not big deal but still a deal.
Bear in mind that he didn't do 12 hole injectors with cranked up pressure, two speed fan or lock out hubs or any of that goofy space ship looking aerodynamic crap. I think he did pretty good getting 24 mpg considering the original EPA milage estimate was 19.

 

New member how do you start a new post or ask a question for help. Saw you just posted .ty