Contour Enthusiasts Group Archives Forums Modifications Zetec Performance What kind of gas milage do you get wit your zetec?

I bought the Valvoline Complete Fuel System Treatment and it didnt help me for SH!T. What other liquid could/should i buy to fix this (that is proven to work).

"You have to restart your odometer when you get gas. Next time you get gas, record the gallons you put into and record the mileage on the odometer trip thing. Use those to figure it out. Gas mileage is affected by everything. Check tire pressure, clean or replace anything that could be dirty. Air filter, oil, oil filter, clean injectors, replace pcv valve, check for air/vacuum leaks, replace fuel filter, don't drive the car hard."

1. i dont know ho to check tire pressure (whats average?)
2. I cleaned the injectors with the injector cleaner (did that with the complete fuel system treatment)
3. where do i get it and how do i replace pcv valve?
4. where could the air/vacuum leaks be coming from?