1FZFE fuel mileage

[DodgeH8TER]

So I finally got my second top off on the 80 series and needless to say I was a little shocked on the fuel mileage. I bought the cruiser knowing it wasn’t gonna get good fuel mileage but 8mpg with mostly city driving and a few trips down the freeway. I thought it would do better than a 454 or yet alone the 2UZ. I let it warm up for tens minutes depending on the temperature considering I’m in Idaho and it gets a bit chilly here. Just checking if this is normal. I’ve read up that it’s supposed to get about 11mpg in town. My dad’s 100 series gets 13 in town. I do got a check engine light that I haven’t scanned yet, if it’s an O2 sensor or a MAS then that will probably answer my question. And I don’t floor it every where I go, nice gradual accelerations unless I’m merging into traffic

 

[ajax1]

Scan it
Fix that
Then do a baseline tune up on the whole truck.

 

[Batameez]

Idling for ten minutes will get you 0 MPG. Not that it's bad practice but not surprising. Mine was just as piss poor due to that and city traffic.

 

[DodgeH8TER]

Idling for ten minutes will get you 0 MPG. Not that it's bad practice but not surprising. Mine was just as piss poor due to that and city traffic.

I kind of have no choice. It gives the car time to warm up and also defrosts my windows

 

[DodgeH8TER]

Scan it
Fix that
Then do a baseline tune up on the whole truck.

By tune up do you mean just replace parts that effect fuel mileage

 

[mudgudgeon]

By tune up do you mean just replace parts that effect fuel mileage

That would be maintenance.
And yes, making sure spark plugs, leads, distributor cap and rotor are all fresh or in good condition will all help. Along with fuel filter, air filter, making sure you have no vacuum leaks etc

Tuning would be checking the timing is correct. Beyond that, there's not much that can be tuned on a stock EFI engine

 

[DodgeH8TER]

That would be maintenance.
And yes, making sure spark plugs, leads, distributor cap and rotor are all fresh or in good condition will all help. Along with fuel filter, air filter, making sure you have no vacuum leaks etc

Tuning would be checking the timing is correct. Beyond that, there's not much that can be tuned on a stock EFI engine

Haha. Speaking of vacuum. Would my collapsed vacuum line cause this. I think it runs to my Map sensor but could be wrong

 

[mudgudgeon]

Any vacuum leak is gonna mess with fuel economy and how well the engine runs in general.

 

[DodgeH8TER]

Any vacuum leak is gonna mess with fuel economy and how well the engine runs in general.

Well I’ll probably look into replacing all my lines then. Rubber degrades and I can guarantee that they are original

 

[manofthewoods]

I kind of have no choice. It gives the car time to warm up and also defrosts my windows

Running enough to defrost windows is well past any warmup that is beneficial for the engine. That's what is significantly dropping your mileage.

A potential alternative might be to start the engine and quickly use a scraper/brush on the windows. Might be 2 minutes. Assuming easy ish driving for 5 minutes - you'll see some improvement.

 

[BILT4ME]

EVERYTHING affects gas mileage.

I replaced my rear calipers, rotors, wheel bearings, and LSPV. It increased my mileage from 11 to 12.5.

I changed plugs, wires, cap, rotor, all vacuum hoses and went from 8 to 10.

I installed 285/75-16 tires from the stock tires and went from 13 to 11.

I changed tire pressures from 32 to 40 and it went from 11 to 11.5.

Depending on where you are in your maintenance schedule, you mileage will reflect that.

If I drive at 35 mph for an entire day, I can get 19 mpg. If I drive at 75 mph I get 11.

I put on 15K to 20K miles per year and I make notes on what I change and repair and watch mileage.

I have averaged 11.5 for years. Wind and weather also affect it. 9-10 in winter. Best mileage is about 65°F, no wind, keeping it slow.

Best I've ever seen was 21 on a short fill, driving 25-35 mph for 180 miles on gravel roads. Worst I've seen is 4.

 

[Devils Paw 80]

You should be getting at least 11 in a stock 80 series around town, usually more like 12-13.

 

[SoTexCruiserDoc]

EVERYTHING affects gas mileage.

I replaced my rear calipers, rotors, wheel bearings, and LSPV. It increased my mileage from 11 to 12.5.

I changed plugs, wires, cap, rotor, all vacuum hoses and went from 8 to 10.

I installed 285/75-16 tires from the stock tires and went from 13 to 11.

I changed tire pressures from 32 to 40 and it went from 11 to 11.5.

Depending on where you are in your maintenance schedule, you mileage will reflect that.

If I drive at 35 mph for an entire day, I can get 19 mpg. If I drive at 75 mph I get 11.

I put on 15K to 20K miles per year and I make notes on what I change and repair and watch mileage.

I have averaged 11.5 for years. Wind and weather also affect it. 9-10 in winter. Best mileage is about 65°F, no wind, keeping it slow.

Best I've ever seen was 21 on a short fill, driving 25-35 mph for 180 miles on gravel roads. Worst I've seen is 4.

That was a beautiful description. It should somehow be flagged in perpetuity on MUD. And like deserves a page in the FSM…

 

[Marvelicious]

There are thirsty beasts, but it sounds like you've got some deferred maintenance to take care of. I'm sure you'll see a significant improvement, but it's never going to be a Prius!

 

[TWILLY]

Diagnose, repair.

 

[FIDO96]

I have a 97 LC. Everything is stock except suspension and tires (33”). Engine has been baselined, all new hoses, wires etc. We recently replaced the EGR and VSV and cleaned the upper intake manifold to rid the legacy P0401 code. Added a new tank, charcoal canister and fuel pump/sender, etc. It idles perfectly, runs strong and gets 12.6MPG consistently. I’ve been using the PWR setting recently as I mainly use it for daily highway driving and that’s knocked it down to 12.4 but I also am heavy on the gas more because it’s just so damn fun.

 

[NeverFinis]

I don't think anyone has mentioned, but gas formulation can change seasonally. Since the OP is in Idaho, they are most likely using "Winter Gas", which drops MPG compared to the Summer formulation.

BTW, my 360HP L96 V8, with 35" tires, seems to be getting over 15 MPG. More driving is required to certain of its MPG.

 

[DodgeH8TER]

I don't think anyone has mentioned, but gas formulation can change seasonally. Since the OP is in Idaho, they are most likely using "Winter Gas", which drops MPG compared to the Summer formulation.

BTW, my 360HP L96 V8, with 35" tires, seems to be getting over 15 MPG. More driving is required to certain of its MPG.

In Idaho we don’t have winter formulas for gas. Only in the diesel to help it not gel up in at the station. But you gotta add some sort of additive to stop it from gelling. I run 85 octane which could affect my fuel mileage but I don’t think it will because it’s a low compression engine therefore higher octane fuels shouldn’t give me any benefit. Come spring I’ll probably know my true fuel mileage but I’m gonna start replacing parts because I can guarantee it’s long overdue

 

[Kernal]

@DodgeH8TER : what tire (Size/Brand/Tread design) are you running and at what PSI?

If you're running a Mega Tread Off-Road tire expect less MPG compared to a SL (Standard Load) all-season tread tire, and much worse MPG if the tires are not inflated enough depending on the tire and load. Higher PSI can lead to a harsher ride depending how high you go, different tires will have a different PSI sweet spot IME.

 

[DodgeH8TER]

EVERYTHING affects gas mileage.

I replaced my rear calipers, rotors, wheel bearings, and LSPV. It increased my mileage from 11 to 12.5.

I changed plugs, wires, cap, rotor, all vacuum hoses and went from 8 to 10.

I installed 285/75-16 tires from the stock tires and went from 13 to 11.

I changed tire pressures from 32 to 40 and it went from 11 to 11.5.

Depending on where you are in your maintenance schedule, you mileage will reflect that.

If I drive at 35 mph for an entire day, I can get 19 mpg. If I drive at 75 mph I get 11.

I put on 15K to 20K miles per year and I make notes on what I change and repair and watch mileage.

I have averaged 11.5 for years. Wind and weather also affect it. 9-10 in winter. Best mileage is about 65°F, no wind, keeping it slow.

Best I've ever seen was 21 on a short fill, driving 25-35 mph for 180 miles on gravel roads. Worst I've seen is 4.

I’ll have to start fixing stuff. Truck is currently not stock because it’s got a 3in OEM lift. But that won’t affect stuff to bad. stock tires but they could be affecting my mileage because they are older than I am.
I’ll probably be killing my mileage a little more because I plan on putting on some 35x10.5R16 or 17(pizza cutters are the way to go)

@DodgeH8TER : what tire (Size/Brand/Tread design) are you running and at what PSI?

If you're running a Mega Tread Off-Road tire expect less MPG compared to a SL (Standard Load) all-season tread tire, and much worse MPG if the tires are not inflated enough depending on the tire and load. Higher PSI can lead to a harsher ride depending how high you go, different tires will have a different PSI sweet spot IME.

so it’s got three Hercules A/T 265/75R16 6ply and one Toyo A/T same size 10ply. I run them all at 35 psi. I’m about to get sone Mickey Thompson Baja Champion 35x10.5R16 and I’ll run them at 40.