oh my god- a 0.8mpg decrease!
Seriously, your truck is a 96 model. When did you get the injectors tested the last time for example?
Injector wear, uneven spray pattern, low pressure can cause that.
On the other hand you do have to do your calculations over a longer period of time to get an average.
Most people do not understand that an engine is a complex system. Changing a single item into a better one may not give you the expected mpg increase depending on the engine.
Maybe you have increased your hp, but more hp needs also more fuel- so the fuel saving advantage diminishes.
Less backpressure is a good thing to start with. Now check the engine and proceed with engine adjustments. Your torque curve and your powerband will move to a different spot due to the less bp. Find it!
Last edited by Deezel Stink3r; 02-27-2011 at 06:02 AM.