i have an 89 f150 with about 98000 miles i used to get about 225 miles to a tank of gas now i get about 140 in a day i used the same gas from the same station as i normaly do but i did get new tires same size just new ones (31-10.50-r15) does anyone have any clue why this would happen. here are some things ive tried

1)new plugs
2)bottle of fuel enjector cleaner
3)Cleaned air filter
4)made sure hubs were unlocked
5)bottle of dry gas
6)checked and topped off oil

Thanks in Advance

 

have you pulled the codes? if you dont have a code reader, got to www.fordfuelinjection.com and read up, its pretty easy.

 

When was he last time a complete tune up was done....also pulling codes is always the best place to start

 

wow thanks i never knew you could do that with out the reader this helped alott thanks

 

ok i pulled the codes and in know what all of them mean but this one EVP circuit below minimum voltage of 0.24 volts. could this effict gas milage and how if i have to do i fix it. thanks

 

do you have a manual?

if not get one, it will help you a lot.

 

i have a chilton manual is that what u mean? or is there a code book?

 

then you can look up how to fix your evp circuit.

a chilton will have a code page.

is convertor or exhaust clogged?

did you check wires, cap, rotor?

did it suddenly change mileage from one tank to the next?

 

The evp below minimum voltage means that the computer is seeing too low a voltage back from the EVP. Therefor either the EVP is bad or there is a problem in the wiring or connjectors; such as corrosion. You can test the EVP and check the voltage manually to verify if its truly bad. Chiltons should have a procedure in testing the EVP.
Tim

 

The EVP is the EGR position sensor, located on the top of the EGR valve. I suggest the Haynes manual over the Chilton's, based on my personal experience with both of them. I have both and the Haynes is much better. The converter will not get clogged over night. What were the other codes you got? Check the fuel pressure and the fuel pressure regulator. The regulator has a vacuum hose on top of it - pull that hose and if there is gas in that line, the regulator has broken internally and is allowing fuel to get sucked straight into the manifold, killing fuel mileage.

 

i agree, the haynes is better. i have factory manuals and they are best. i was just suggesting he at least had to have one manual.

he did not ever say if it was overnight with his problems. i just wrote a list of possible things to look at.

i agree that he should post any other codes and check regulator.

 

ok these are the rest of the codes i got and thanks for all the help guys without yall i would be lost and poor.67 Neutral safety circuit failure.
77 System failed to recognize brief WOT during Dynamic Response Test (user error).

i pulled the codes three times to make sure i got them right and on one of the times i got 3 flashes so im guessing thats 30 (Cylinder #3 Failed Cylinder Balance Test). but i only got that code once is that bad im guessing it is.

thanks alott guys your a huge help

 

Hmm, it shouldn't be a code three because the trucks won't do a cylinder balance test. I'm not really sure what is going on. Did you run the test with the engine off as well? If not, I'd do that because some codes will be stored in memory and may not show up in the engine running test.

 

i pulled the codes with the motor on and off im going to try and take the egr off test and clean it and see what it does thanks for the help!

 

I got one from advanced auto that said my #2 failed balance test? HMMM