What is considered BAD Fuel Economy for the 2.7 Liter?

I bought a '98 Extended Cab 4X4 2.7/Auto a few months back with 177k miles in very nice shape but the Sunfire Red paint was slightly faded, and the interior needed freshening so I went full monte and redid the interior and refinished the exterior in the 2 tone 4Runner Limited scheme (Sunfire top, Silver below) figuring it would be a long-term keeper and the truck is beautiful and I love it. It runs great, shifts beautifully, and handles well.

The fellow I bought it from bought a 2017 Chevy 1500 because he gets 26mpg local driving and it has great power he says, and he's touched 30 mpg on the Interstate.

I changed the trans fluid, synthetic oil, installed new spark plugs, and checked the cranking compression ratio with all 4 cyls between 202 and 205 psi, which I thought was outstanding. The engine has a K&N in a stock housing, a TRD tube header, and larger diameter exhaust Cat-back with a Flowmaster, but is completely stock internally.

But somehow either I didn't realize how thirsty the 2.7/Auto is on fuel, or something is wrong. I am an extremely conservative driver with a light foot, and always manage to get great mileage on whatever I drive. My Dodge Cummins crew cab dually (2WD) 6spd gives me 26+ on the highway and 22+ around town, so frankly I thought I should be able to nurse 22mpg around town with the Tacoma driving it like I was your Aunt Gertride feather-footing it, hypermiling it, allowing it to shift early never using more than the first inch of throttle or more than 2200 rpm.

But the best I have done is 16 mpg, and I saw a 14mpg tank. I put a sophisticated scanner on the vehicle but everything looked fine on live data. Fuel trim damned near zero, ign avance about 8 deg BTDC at 750rpm idle speed idle, O2 sensor voltage bouncing around a 450mv centerpoint in closed loop like you want to see. I didn't see a thing to indicate anything was wrong.

The truck is sitting on 10.50 31 15 tires, and I'd picked up a set of BF Goodrich All Terrain T/A in size 735 75 15 thinking the slightly smaller diameter might raise the rpm into a happier place maybe make the truck a bit less "doggy," because I would with the 31" tires call acceleration barely adequate (more pedal over that required for constant speed on level ground doesn't produce noticible acceleration). This is the only 2.7 Tacoma I've driven, but without downshifting or switching off OD it's pretty much a dog. I have experience in a friend's 2008 crew can 4.0 liter and it's a rocket and returns 22mpg around town.

Is this normal or what should I look at to make it better?

Thanks,
Bob

 

The 3rz 4 cyl doesn’t consume quite a bit of gas I’m on 33s on my 96 4x4 4cyl and my
Mpg is 14-16 so. Possibly maf sensor?


Edit: does consume

 

I have a 3.4 I think the best mileage I ever got was about 14mpg with a strong tail wind .

Normal for me is 10 to 12 mpg sometimes in the single digits

 

With the 4 banger, you always have it floored just to keep up with traffic, so yeah, gas goes quick. Had 2, 4 pot Tacos, neither got good fuel milage.

 

The fuel economy numbers you gave on the other rides are......shall we say, more then normal.

But yes, Taco's don't get top marks in fuel economy. Never had whether a 4 popper or a 6.

 

I have the 2003 with the 2.7 and get a consistent 19.5-20.5 mpg. The truck has 225,000 miles on it.

 

found this, took about 2.3 seconds search on GOOGLE
https://fueleconomy.gov/feg/bymodel/1998_Toyota_Tacoma.shtml

 

Damn, now that’s sounds like ‘bad’ fuel economy for a 3.4 I get a consistent 19 mpg in my 3.4. Are you running massive tires?
I am not light on my pedal either, to say the least

 

Same here in the PA hills with a 5 speed. Do have to row between 4/5 a bit though keeping the engine RPM at 2 - 2.5k

 

I have two tacos, both 95 models, 4x4, AT, with 265 x 16" street tread tires (alum wheels), but otherwise stock chassis and engines. Both engines have recent plugs, MAFs cleaned, etc. 2.7L has a slight mis-fire at idle that I have not diagnosed.

I am an easy driver and my area, while having rolling terrain areas, not many +75' elevation changes in a single hill. So, I'd call it relatively flat terrain.

2.7L with Michelin tires gets 17-18 with mixed miles, some 4 lane but copious stop lights. This engine has about 170,000 miles. Mileage drops a solid 1-1.5 mpg when I put my 15" steelies w/AT tires on for Winter. Low 17 mpg is typical in Winter with high 17-18.5 in Summer.

3.4L with Firestone LE2s tires get's 18-20 with local miles. This engine has about 260,000 miles.

 

Checked for exhaust leaks? My mileage and acceleration dropped a lot and it turned out the gaskets at the flanges upstream and downstream of the cat were cooked and my exhaust manifold was loose. Not enough to throw codes but enough to make the engine (more of) a dog

 

Just waiting for someone to chime in with “I get 22mpg with 33” mts and armor”

 

Couple of things to consider that may or may not help.

Have you checked the wheel bearings for drag?
MAF and Throttle body clean?
Driveshaft in good condition?
Tire pressure?
Can you get a set of stock rims with stock size tires for a trial?
Serp belt and pulleys in good condition, ie no pulley drag?
Alignment?
What is the truck hauling for extra weight?
Do you use long idle time to warm up the engine on first start?
Winter blend fuel can impact MPG.

My '06 V6 4WD with AT (no mods) is pretty consistent in mixed driving at 19.* mpg.

 

Thanks all.

1) Yes, I checked EPA mileage and mine said 17 City 21 Highway, but I always beat those because I drive gently, which is why I was shocked. As I mentioned, I coax 26-28mpg out of my 7600 pound (empty truck w/ 2 persons and fuel) '03 CRD Dodge Cummins 1 ton with 6 Michelins on the ground.
2) My bad Tacoma mileage is with an EMPTY truck (just me inside, NOTHING but the bed liner in the back) in suburban driving 50 mph or less-no traffic lights, just local rural highways.
3) 10.50 31 15 Cooper tires aired to 30psi on cast aluminum wheels
4) Nothing drugging. I regularly have it up on my lift and all tires rotate easily and I installed all new brakes and no calipers are dragging.
5) No long idles. Start it, wait maybe 30 seconds at MOST before driving off. NEVER use much right pedal, and have never even mashed it to 1/4th, muchless full pedal.
6) My son in AZ has owned a couple of Tundras w/ the 4.7 V8 he bought new (Last one a 2014 for $58k which I couldn't believe) and he is a lead foot . He got 12mpg with the older one and 14 with the 2014, but I chalked that up to his driving style, PLUS the Tundras are bigger and heavier. He put the 2014 on 33" tires now, which is why he's down to 14mpg (from 15 with stock tires).

Frankly I NEVER would have dreamed that a "small" truck like the Tacoma with the 2.7 couldn't make 20mpg driven lightly given my previous Japanese small trucks (2 2WD Mazdas, a 2WD Isuzu, and a Nissan 4X4 King Cab all managed 24-28mpg the way I drove them). and my full-sized PUs did reasonably (Ford F-250 4X4 350 V8 14-15, Ford Supercab 4X4 300 cu in 8ft bed 15mpg, and the 2WD RAM 3500 dually 23-28mpg).

My friend's '08 Tacoma 4WD 4.0 liter auto trans I mentioned does 18-20 in town and 22-24 highway and he has put 300k trouble-free miles on his (the rear springs and headlights were replaced on recalls, but otherwise no problems).

Not trying to just complain, but I honestly thought I would be getting 20mpg suburban and maybe 24 highway based on past experiences and how I drive, and thought maybe there was something I wasn't "seeing" that would be an ah-ha moment to find my lost MPG, but it's sounding like I MAY have nothing wrong except the engine efficiency is very low on these vehicles (fuel flow per horsepower produced), and it's just endemic to the brand. The ONLY vehicle I ever owned that got 14mpg was a '79 Ford Bronco with a 400ci in V8. That was 6.6 liters of engine and a 4500 pound Bronco-not 2.7 like the Toyota!

I LIKE the smaller size of the Tacoma for everyday driving vs. my crew cab dually Ram w/ 8ft bed (When I lived in Texas parking lots were SIZED for trucks like that because so many folks drove similar vehicles, but here in WA State parking is more difficult and rowing a 6 speed around town is less fun), but getting 10mpg LESS on a much smaller truck is hard to justify, though now that I 'restored' the Tacoma with new everything it's such a jewel (I like the styling better than the newer ones by far) I am a bit disappointed.

Thanks,
Bob

 

now you know cause your John Doe

 

Neither of my trucks hit overdrive until about 52-54 mph. That could be your problem. If I got no overdrive miles on mine, I am guessing I'd lose 2-3 mpg pretty easily.

 

Tires are 235/75/15 in my case the low mileage is the wind resistance and weight .

In a few weeks I can get 1000 pounds of cable behind the seats then put another 1000 pounds plus in the bed and maybe tow another 2000 pounds.

I never really checked when empty because that is not very often

 

On mine, with a burnt valve, these were my averages:
Towing MPG 15.45 (16.2 for a full 5x8 uhaul, 13 for a 1/3 full 6x12 uhaul)
Mixed MPG 20.06
Hwy MPG 21.31 (best tank was 23.85)

Thats with 235/75R15 tires, MT and 4.30 gears. I have to really beat on it to get under 20 around town. And it should be better now that the leaky valve is fixed.

Speaking of valves, when were they adjusted last?

 

In response to the thread title, 'starting it.'

 

That I cannot say, but getting cranking compressions of 205 +/- 3psi across all cylinders and quiet running would not point to valve adjustment issues IMO, but I could be wrong. Too-tight valves would ordinarily result in low or inconsistent compression values, while loose often makes noise, both of which would announce themselves.

I admit to being lazy as shim type are not my favorites to mess with, and I don't have access to a box of shims, though I know I can measure each, remove them and determine what one to order for each of the 24 valves then go back in when they arrive and swap them out.

But would that gain me 4-5 mpg? Somehow I doubt it (but I could always be wrong).

Someone mentioned leaky exhaust gaskets. Not a whisper of audible leakage I can hear.

I have had the OD and Torque Converter lock up above 50mpg when I am on a long stretch of 2-lane, but given that we are discussing around-town driving, I doubt most people exceed 52-54 mph much of the time. I have not driven the vehicle significantly on the Interstate but a few miles so cannot comment on highway mileage. I've only driven maybe 280 mi since re-doing my truck so far-a couple of partial tankfuls of 125-150mi each. I did run injector cleaner through one tank just to see if it would make a difference at all.

Bob