I have a 94 F150 that came with a 4.9 & I had it converted over to a 5.0,my problem is it has a rough idell at cold startup, tail pipes are burning black as coal,& only gets 13.5 miles to the gallon. I had it put on a computer & everything showed up ok.
Thanks for any advice.
C.M.

 

?

 

Check for any vacuum leaks; also make sure the IAC connector is plugged in, and also the ECT. Better off, check to make sure all sensors are plugged in.
Did you do the conversion, or did you have it done?
If you had it done, did they do every thing right?
13.5 MPG isn’t bad for gas mileage; I get around 11 MPG or so

 

I had the conversion done,the place that did it has been there for 20 years plus. I read some other topics on here and did what they recomended.(it helped) I haven't ran a full tank of gas thru it yet to check the MPG,but before at a 100 miles it would be on the low side of a half a tank,at a 110 miles it is on the upper side.

Where are the vin numbers at on the 302? They said it was a 302 H.O. but the plugs that were in it did not match the H.O.
Sorry so long winded.
Thanks for the info.
Carl

 

I have had the same problem twice in the 8 years I have owned my 88 with a 351. The computer kept sending me on a wild goose chase as far a codes go. Turns out the fuel pressure regulator gave up the ghost and was sqirting full fuel pressure to the injectors at all times. Tail pipe ran black and milage dropped to about 6-7 mpg range. Replace the triangular regulator and wham-back to normal...Hope this helps.

 

As for your gas milage,,,feel lucky that your getting 13. I get 9-10 with my 95 F-150. Granted it does have 35's on it. But it only got 12 stock.

Ryan