Gas Mileage

I ahve a 1999 Dodge Dakota SLT V6. The V6 Dakota is suppose to get on average 16.5 MPG. 16/21 to be exact. I get about 14.2 on average. This is when I accelerate at a below normal speed. If I accelerate at a normal speed I get about 13.8. This is a V6 I remind you! My tires are at the correct presure, I put in new Bosch Platnum 4 Spark plugs about 1.5 months ago, I recently had the thermostat replaced, I Installed the "Tornado", put in ZMAX, and I put in gas treatment regularly. I know my alignment is off and I need some new tires, but would this alone cause such poor MPG? If anyone has a V6 Dakota, please post your MPG or any suggestions you might have? Thank you very much.

I got rid of the stock muffler on my 96. Opened up the air box behind the grill, and I moved the air temp sensor to read the air from the snorkel instead of the heat from the motor. I went from about 15.5mpg to around 18.5. The stainless high-flo muffler cost me $145 and the rest was free. Plus I have a lot more power. I think it was well woth it.

Synthetic oil can also give a 2-3 MPG improvement.