Sand-Dog
NAXJA Forum User
- Location
- Southwest Florida
The truck: 98 XJ, 75K miles, stock 4x4 (including tires), except for Edelbrock header, K&N cold air system, bored-out TB, Dynomax cat and cat-back.
The issue: I bought this relatively low-miles XJ last summer from a neighbor and modified it slightly (as detailed above) to increase the engine's efficiency. With mods done and the PO's original 10W30 oil I averaged 22 mpg on the road (75mph cruise on Interstate).
This weekend, the same trip showed 18 mpg. The only difference is an oil change: went to 20W50 and a quart of Lucas oil conditioner to increase my oil pressure.
Could just the thicker oil have taken the MPG down that much? Other thoughts? Injector replacement time at 75K??
The issue: I bought this relatively low-miles XJ last summer from a neighbor and modified it slightly (as detailed above) to increase the engine's efficiency. With mods done and the PO's original 10W30 oil I averaged 22 mpg on the road (75mph cruise on Interstate).
This weekend, the same trip showed 18 mpg. The only difference is an oil change: went to 20W50 and a quart of Lucas oil conditioner to increase my oil pressure.
Could just the thicker oil have taken the MPG down that much? Other thoughts? Injector replacement time at 75K??