I had experienced a decrease in fuel mileage in my 98' XJ, combined with a rough idle and at 107k I figured it was time for a tune up..
Well, I replaced all the plugs with autolite platinum's, new plug wires, a cap and rotor. At first it appeared that the rough idle was gone, but now since i've put a few hundred miles on it the rough idle is back and the mileage never really did make a recovery.
Now that I've lifted it 2.5 more inches and went with a 33" tire instead of 31's it has gotten worse, which I totally expected and I realize the mileage will never fully recover but I would like to get rid of the rough idle for good.
Well, I replaced all the plugs with autolite platinum's, new plug wires, a cap and rotor. At first it appeared that the rough idle was gone, but now since i've put a few hundred miles on it the rough idle is back and the mileage never really did make a recovery.
Now that I've lifted it 2.5 more inches and went with a 33" tire instead of 31's it has gotten worse, which I totally expected and I realize the mileage will never fully recover but I would like to get rid of the rough idle for good.