Poor MPG

WABronc

New member
Joined
Aug 26, 2020
Messages
3
Location
Seattle, WA
Update from my previous post, it seems that the rough shifting into reverse was just me letting the gears bind when parking on my sloped driveway. Transmission bumps a little from time to time between 1st and 2nd but it doesn't seem concerning. Front brakes have been swapped out and no longer squeal. Replaced a lot of the interior lights with LEDs as well.

Current issue is I'm halfway through a tank of gas and I'm averaging about 8 MPG (almost all city diving, so I expected it to be low but not this low). First things first I will swap out the air filter (I've seen K&N suggested), but what else should I be checking? I know it's a basic question but any help is appreciated.
 

Tiha

Member
Joined
Jul 22, 2020
Messages
59
Location
Midwest
Sorry, what are the specs? Engine? Miles? Lifted or not?
I had a 96 and I tried everything I could find on the internet and never got over 12.5

My son had a 94 with 33" tires and never got over 10 no matter what we did. But then he was also driving like a kid.
 

Tiha

Member
Joined
Jul 22, 2020
Messages
59
Location
Midwest
yeah but 96 was MAF 5.8 Much easier. Than 95 and older 5.8s Would have though 14 or better was possible but apparently not.
 

miesk5

96 Bronco 5.0
Staff member
Moderator
Joined
Oct 18, 2005
Messages
7,827
Location
Coronado, CA
Yo WABRONC,
Does check engine light appear while driving?
Due to age, it's common for Fuel Pressure Regulator (FPR) diaphragm to fail, allowing high pressure gas to leak into it's vacuum line, which then dumps straight into the intake plenum. This can flood the engine, and if allowed to continue, it can wash the rings out & damage the bearings. To check it, simply disconnect the vacuum line with the engine idling & inspect for the presence or any aroma of gas.
It may take a few seconds for the FPR to fill with gas and begin spitting it out the FPR's engine vacuum nipple.
Also;
Check Timing
Try Sixlitre Tune-Up @ ignition upgrade and timing bump (no 56K!).

Restricted air inlet or dirty air filter causes excessively rich fuel/air mixture

Worn spark plugs cause inefficient combustion, wasted fuel

Worn O2 sensor unable to detect and adjust air/fuel mixture without a DTC.

Dirty or substandard engine oil Increases internal engine friction.

Loose gas cap allows fuel to evaporate .

⊙⊙⊙
 

WABronc

New member
Joined
Aug 26, 2020
Messages
3
Location
Seattle, WA
So far I have only gotten around to inspecting the air filter, which seemed fine although it looks like I need a new breather filter. Haven't found anything that seems to be the problem yet and haven't found any time to work on it besides some cosmetic stuff.

@miesk5 big thanks for that tune-up post. I'll follow along with that this weekend.

Also someone asked: the truck is all stock 5.8L 351, 31" tires. Not lifted. 141k miles.
 

ragtop69

New member
Joined
Dec 23, 2019
Messages
26
Location
Lincoln, CA
I had an '83 XLT with a 302/C6 that, when new, got 13 mpg going up the Sierras and 13 mpg coming home. Had it for 17 years and at the end it was getting 7 mph around town. I've never even measured my '95 XLTs mileage. As a Bronco owner you just learn to stick that hose in the tank and wait for it to click off. With those 32 gal. tanks it might also be advisable to have a line of credit with the bank. Especially here in CA.
 

Members online

No members online now.

Latest posts

Forum statistics

Threads
21,304
Messages
123,990
Members
22,988
Latest member
tdmwi
Top