- Joined
- Apr 22, 2021
- Messages
- 103
- Reaction score
- 42
- Points
- 28
- Location
- Spokane, WA
- Vehicle Year
- 2000
- Make / Model
- Ranger XLT
- Engine Type
- V8
- Engine Size
- 5.0
- Transmission
- Automatic
- 2WD / 4WD
- 4WD
- Total Lift
- 3"
- Tire Size
- 245/75R16
I swapped in a freshly built 5.0 about 3000 miles ago. everything is new, and mostly motorcraft parts, minus the spark plugs and 02 sensors. I was getting about 17 mpg in the city when i first started driving it. but its down to about 9 in the city now and 15 on a pure hwy drive. I'm trying to figure out why its so bad. I did have my cam position sensor go out on me, which i replaced, didnt time, and after about 2 weeks i went back in and timed it properly, and replaced my spark plugs. but still, terrible mpg. my only thoughts now are a vacuum leak, or bad 02 sensors. I went around and replaced the questionable vacuum lines, then went around with propane and tested all the places there could be a leak, it seems to be all tightened up. so now my only guess is the 02 sensors. my b2s2 jumps all over the place, while my b1s2 stays basically the same while idling. my short term fuel trim is pretty steady on bank 1 around -1.6 -> .8 -> 1.6. my bank2 short term is around -3 -> +3. so obviously these are still "within spec" but im thinking about getting some motorcraft upstream sensors to do the sensing. I've also heard that MAF could be causing the issue, that was hanging at .8lbs/ min at idle with the TP at 18%. I've been trying my best to make sense of these numbers since its my first time even looking at fuel trim. I already have a new MAF sensor that I was going to put in when i rebuilt everything, but ended just sticking with the OEM one (because i'm lazy and the OEM one seems to be working). I know i'm kind of just throwing parts and money at a problem trying to solve it, but its the best i could do, but i'm sick of doing that, and neeeeeeed to get back to the 17 mpg. I cant drive a half size truck on 9 mpg.