steveokeneivo

Hey guys I got my truck running after replacing my ECU but was wondering what gas mileage you are getting? I have an 86 5.0 FI 4 speed auto with overdrive, 33's and stock 3.55 gears. I have had this truck for about 3 years and for the last 6 months I have had it as my daily driver. I only get 10 in town, with a light foot and I can get a whopping 11.5 mpg on the highway doing 55mph. I have always had the same gas mileage but it didnt affect me as much when I would ony take her out on weekends. It has new plugs, wires, ignition module, fuel filter, cap and rotor, fuel pressure regulator is good. I do have a code 31 for the EVP but I switched that one and I still have that code and I cleaned the EGR. I dont expect to get 20mpg but I found specs for 14 city, 17 hwy. Maybe Im missing something thanks for the help guys, Steve.

klricks

You are getting better than that due to the larger tire size. You are going further than your odometer indicates.

Try this of one of the many on-line calculators.
http://www.1010tires.com/TireSizeCal...?action=submit

My OE tire size is 235x75xR15. I am running 31x10.5xR15 so the speedometer/ odometer error is 7.266% for me. (Not including any error already present).

Or get a GPS and measure your GPS speed against the speedometer. Find the % of error and apply that to the odometer.

steveokeneivo

It was 12.67% off so that would put me at about 12.5city/ 14.5 hwy. Not too bad. I was wondering if switching gears would pull the 33's easier and maybe pull a little more mileage, or if it would be worth it to go down to 31's when these tires are done. It doesnt like hills much. Will kick down into 2nd gear which I understand with the gearing. For the most part I dont go into the mountains much with it, but if it did a little better I would. Is there somewhere we can order those gears for the speedometer to correct the speed? Thanks, Steve