Everytime I do a performance upgrade my fuel mileage increases for about one tank of fuel. For example: I put a K&N filter and saw my fuel mileage increase from 14mpg to 15mpg. After a while it dropped back to 14mpg. I put a high flow catalytic converter, Hooker Heartthrob muffler, and 3" exhaust pipe from the converter back. Fuel mileage went from 14mpg to 19mpg. Again, it went back to 14mpg. Lastly, I put on a Volant Ram Air intake system on. 14mpg-17mpg and back to 14mpg. I would like to install a Performance Distributers FirePower ignition kit, but I am afraid the same thing will happen. A friend told me I needed to install high performance O2 sensors. Another told me to have my ECU reprogramed or install a high performance ECU. Does my truck's computer keep re-adjusting its settings to compensate for the changes I make? What should I do next to improve my fuel mileage and performance?
Apr 12, 2009 at 9:46 PM