truck 91 king cab hardbody 4x4 4cyl (ka24) 5 speed

entirely stock other then 31" tires ( and no its not the tires because the milage sucked before i put them on ) i have changed air filter, plugs, cap, rotor, pcv valve, exhaust flowing fine passed an emissions test 2 months ago no CEL.

im getting about 350 km or about 220 mi to a full tank which is about 14MPG!!

i know these arn't great on fuel but this is ridiculous i gotta full size sierra with a 350 pulling better milage lol

thanks in advance

did you replace the fuel filter?

yup forgot to mention that

How big is your tank? On my D22 it says 15 gallons, but I only ever gt about 11 gallons burned until the gage is on empty and thats about 220 miles.

my tank is 15 gallons or about 60 liters and i easily put 50 liters or 14 gallons in when i fill up

I own a 98 Frontier 4x4 KC 4 cyl and I am getting the same mpg. 31 BFG MT, Warn 9000, Camper shell and rock slidders. Put it on a diet if you want better mpg.

camper shell is not on it anymore its flippin naked lol i refuse to believe any vehicle should get this king of milage lol

I'd be luck if I got 14 mpg. Maybe downhill all the way.

I average 18 w/ mine :P

O2 sensors been replaced in the last
60000 miles,and look at the cat for clogged honeycomb?

14 is a little low for a 4cyl. My v6 get 12-18mpg. My 2wd get between 20-25 in town.

The 4 cylinders should get slightly better gas mileage. Also when you upgraded the tires you are going further than what your odo is reading.

Ya 14 isn't too good for the 4 cylinder. I have 33x12.50 MT's on my 95 4x4 with a vg33e in it. I get a combined average of 15-16 mpg... and that doesn't make me happy.

Obviously you went through all the normal tune-up on the truck... so the next things i would look into are...

clogged cat - before working at nissan ive never heard of anyone ever having a clogged cat before. I always thought it was just some BS myth, but sometimes they get clogged and just choke the engine up badly. Or sometimes if you have two or three... the front ones will break apart and fall down into the third one and clog everything up and cause the engine to lose alot of its power and gas mileage. -just because it passed emissions doesn't mean the exhaust is flowing good.

compression in the cylinders- possible slow leaking head gasket, burnt up piston rings. Oil consumption issues?

02 sensor - after putting the vg33e in my truck it ran great and had normal gas mileage for about 6 months... then it started to stall, get bad gas mileage and idle funny only when i first started the engine. After going through and replacing every part you mentioned as a tune up procedure, i just tryed unplugging the 02 sensor ... It was night and day difference. the problems went away, and my gas mileage went back. I've been driving it without the 02 plugged in for a few months now and its been running awesome. I realize i could just replace it, but i dont believe it will improve my mileage or performance because im getting better response and mileage then when the 02 sensor was in working condition.

I get 14-15 in town without correcting the odometer for the oversize tires with my 4banger and 33s. Engine just may be tired. When i replaced my timing chain i actually picked up 1 more mpg on mine.

My mpg has gone up and down allot in the past 2yrs. when i was overheating it went down to 11 changed the radiator it went up to 13 city 15 hwy.
installed headders and it went up to 13.5city 17 hwy
the themostat locked open (overcooling) and it went back down to arrond 11.5 city (didn't get on the highway then)
fixed that, replaced O2 sensor, K&N filter, installed magnaflow high-flow cat & muffler all @ same time and I now get 13.5ish arround town and close to 20 mpg on the higway.

all this is with 31x10.5 tires & 1.5" torsion bar crank (effects wind resistance)

You might check that the rear drum brakes aren't dragging. They can typically get left out of brake jobs in my experience.

As you know, how you drive the truck has a huge affect on the mileage too. If you are flooring it down back roads a lot, then I'm not surprised. Before it died, I would tend to drive my 1993 4-cylinder pretty easy and average about 17-19 mpg over a tank.

Good luck!