hi all, i have a 95 jeep xj with a 4.0 ho. when im driving down i75 in 5th gear i hear what seems to the valves hitting the pistons. strangly enough it doesnt do it all the time. just in 5th gear and when its cold. i have 31 inch tires with the stock 3.07 gear in the rear. i thought maybe that was part of the problem. but its raining to day so i cant put the stock tires bck on to found out. any help would be greatly appriciated.

 

guess this jeep has a manual AX-15 trans?

 

Sounds like Spark knock (pre-ignition) to me...try a different grade gas and see if it helps...Tj

 

Yes it's got a ax-15 4x2 soon to be a 4x4

 

ditto on trekker. pre ignition. or labor knock. certainly not valve contacting a piston. thing go BANG when that happens.