Loss of highway mpg

demontang · #1 Fri, February 24th, 2012, 12:53 PM

Ive noticed a loss in my highway mpg. I've gone from 16+ to 8-11mpg? I noticed some of it after I took 3" of lift off and went down 4" in tire size. I've got 3.73 gears 4"lift and 33" tires.

***88Racing*** · #2 Fri, February 24th, 2012, 02:18 PM

Make sure when you used custom options and redid the new tire size that you also checked your gear ratio also....

demontang · #3 Fri, February 24th, 2012, 03:47 PM

I'll check that I just put new rims and tires on today because the old ones where to loud for me lol and the rims had almost no clearance on the calipers. It feels like it takes less pedal now but I don't think that's the problem.

demontang · #4 Fri, March 23rd, 2012, 12:18 PM

Ok got my custom tunes and Im running the 87 performance tune right now. I'm getting 13-14mpg intown running 30-45 mph but when I hit the freeway Im getting 4-8 mpg a tank

even going do a steep hill it only reads 8 mpg?? Ive pulled the codes and only get p1000 and Ill get that cleared by doing the run cycle and after it sits over night that code comes back. Ill get code p0420 and p0430 once a week now which is because I dont have cats or maybe the O2 is going I dont know. The highway mpg has me confused though

***cleatus12r*** · #5 Fri, March 23rd, 2012, 12:33 PM

You need to do an ACTUAL test over a few tanks of fuel with actual mileage (make sure your odometer is correct) and gallons used. Watching the overhead display is by no means accurate.

***Longshot270*** · #6 Fri, March 23rd, 2012, 02:26 PM

Quote:

Originally Posted by cleatus12r

You need to do an ACTUAL test over a few tanks of fuel with actual mileage (make sure your odometer is correct) and gallons used. Watching the overhead display is by no means accurate.

X2, your mileage reports need to be a calculation that you do at every fill up. Even though we are in the 21st century computers are still really stupid. They are only made to appear intelligent.