Bigguy-I mostly deal with CJs--Headers may help improve your situation.A little!
But I would investigate your "CODES", Does the check engine light work. Is it on? Maybe you are running "Closed Loop" (the computer is not receiving real world data, from the sensors, and is Substituting it's own Pre-set values to keep the engine running. Running, not efficient!) EX. O2 sensor does not give computer "real data", till it's warmed up---computer substitutes EGBERT the NERD'S Data installed at the factory, until the O2 sensor comes online. This holds true for other sensors also.
Your rig has some age---REALLY Look hard for vacuum leaks, the flimsy rubber connectors are disintegrating now. I sometimes shove a piece of 1/2"-3/4" inch--several feet long, Heater Hose in my ear, and use the other end like a stethoscope to listen for faint hissing. Some vacuum lines are hard tubing, inside Wire Looms, if they break, it's hard to see or find the breaks. Sometimes you must carefully peel the splits open (wire loom) and look and tug on the lines.
I get about 18 MPG with my 6 cyl and 4 bbl Holley, on my '77 CJ 5 (Mr. Jeep)--a 21 Gallon tank was "a must", I was filling up every other day with 15 gallon on my long drives to work.
"Willy" gets about 11-12 MPG, 'course he has a 5.38:1 Gear Ratio, "Mr. Jeep" is 3.54:1
PLEASE LET ME KNOW, YOUR JEEP IS DOING BETTER!
Pics are always a nice welcomed touch!
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Tuesday, May 10th, 2011 AT 3:39 PM