I have a 5.0 1992 f150 that has a longblock from discount auto parts and new fuel injectors. I cleaned all the other parts and now driving it I'm only getting 10 mpg is that really low or is it just me. My friend says it's low cause we couldn't find a knock sensor to install anyone else have a similar problem.

 

I'm sure no one else has this problem, and you definitely couldn't find it by searching.

 

Thanks for the constructive help but I didn't really find anyone with same situation

 

2wd or 4wd, and which transmission? If it's a 4wd with the C6, that's not terribly far off for in-town mileage. 11 city, 12 highway using the revised EPA numbers.

 

2wd and automatic not sure anything else

 

I got a 90 w/a 5.0 and a 5spd and I'm not even getting 10.... Course I got a 4x4 and 33" tires

 

I've got a 95 with a 302 automatic and 4x4 and I am getting 11 mpg.

 

I've got a 94 2wd w/a 5 speed and 31in tires and I get about 18-20 mpg

 

My 96 has the 300 I6 with 33x12.50s and I get 9-10mpg.

 

Do error code scans & deal w/ any active codes. http://www.handsontools.com/Equus-In...ol_p_5574.html
Seafoam treat the engine https://www.f150forum.com/f33/how-se...-1991-a-31505/
Check for vacuum leaks
Replace o2 senors w/ over 60K miles
Transtune treat the transmission
Switch to Synthetic fluids
K&N drop in air filter only if not a MAF engine
Do this Ingition System upgrade Mod (includes stretching plug gap & further advance of base timing afterwards) http://fullsizebronco.com/forum/show...ht=timing+bump
P/u a Haynes repair manual
Stick w/ 87 octane
Stock tires properly inflated
Don't lift
Lucas Injector cleaner periodically
Conservative driving style.

My 87'302 gets 20mpg @ 65mph (your results may vary/ depending on stuff like your cylinder compression, tire size, added lift, gear mods, How fat your girlfriend is, ect...)

All it take's is a bad ECT sensor to guarantee you will not exceed 10 MPG.