Hey I had to have a rebuilt motor put in my truck had a friend who works for Ford hook me up with a discount was still over 6000.00 no problem with the motor but I've been noticing a decrease on fuel mileage the original fuel injectors were used in the rebuilt motor I thinking I might need to replace them since everything else is new the fuel injectors are the only thing left I know they are a pain to replace you have to take off the intake to get to them theres over 120,000 miles on the vehicle I really don't want to replace them but will if I have to

 

O2 sensors set MPG
O2 sensors are the ONLY sensor that wear out on a schedule, 12 years or 100k miles
And as they wear out MPG starts to go down, very slowly but down it goes

Leaking fuel injectors would cause hard or no starts, and misfires, and a drastic drop in MPG i.e. under 10MPG

 

So the engine been doing hard starting and after it start the engine starts shaking I'm gonna check the fuel pressure does anyone know it's supposed to be

 

1986 thru 1997 Rangers used 35psi fuel pressure, called a Return system, has fuel pressure regulator(FPR) on the engine end

1998 thru 2011 used 60psi fuel pressure, called a Returnless system, has FPR in the gas tank with fuel pump

Rangers had no fuel pressure sensor, but computer and engine will usually run fine +/- 5psi