MPG problem or buyer's regret?

I purchased a used 2002 V6 3.4l TRD Tacoma access cab with a supercharger, Toyo A/T tires, a few weeks ago. The MPG seems very low, like 12 MPG in the city.

This is my first 4x4 vehicle and I don't know much about them. Does 12 MPG sound normal? Before purchasing it, I read that the supercharger decreased mileage about 1 MPG so I was expecting my city mileage to be 18 MPG. My driving style is very conservative.

I was told by the seller of the used vehicle that the supercharger could be adjusted by a performance tune shop, but the shop I visited in LA (Dirty Parts) said there was nothing they could do.

Any suggestions? Thanks.

 

Is it completely stock suspension wise? Something is wrong there, with 3" lift and 285's I am getting 15ish

 

Well your truck is rated for 15 in the city prior to the super charger

http://www.fueleconomy.gov/feg/findacar.htm

I am not shocked to hear you are getting 12mpg with winter fuel with a supercharger. You can always get the 4cyl

 

I would suggest cleaning your MAF sensor. Just a thought that before the SC was installed the truck may have had a K&n Air filter, which sometimes messes with the MAF. However I don't know what exactly may have changed when the SC was added? May also need to have it tuned.

 

I think there is a 2" or 3" lift in the suspension.

I forgot to mention, I am not using high octane gas yet. My next tank I will. I was told that the computer might reduce the mileage to avoid knocking.

I found a video about how to clean an MAF sensor on an FJ Cruiser. http://www.youtube.com/watch?v=qiEdey2IHcc Does anyone know where the MAF sensor is located on my 2002 Tacoma? Is it easy to get to or embedded inside the engine?

I saw some other posts about the oiled air filter messing with the MAF. I don't know what I have. Should it be replaced?

I took the truck to Dirty Parts in Culver City, CA and they said there was nothing to tune. Maybe I am not communicating with them. Do I want a Dyno tune? I found a place called DC Performance, Inc. on Livonia in LA. Any other suggestions as to where to take it in Los Angeles?

Thanks to everyone who replied.

 

For finding and posting the vid.+1

 

Don't forget it you have larger than stock tires on there it'll screw with what you're perceiving to be your shitty mpg. Where in actuality you're traveling further than the odometer is sensing.

 

Where do you live?

If you live in a cold weather climate where the gas mixtures change in the winter...you're gonna see poor gas mileage in the winter. Along with lift, tires, supercharger - it'll make it even worse.

My own truck - stock 07 4.0L will see 18-19mpg in the warmer months with standard gas mixtures. In the winter, I'll see 16-17mpg with regular driving. If I allow the truck to warm up on really cold days, I can see gas mileage get down to 14mpg.

I'd experiment a bit with gas octane and see what happens. If you live in cold weather....definately wait until late spring to see if things improve. Assuming everything else is maintained and working properly.

 

I live in Los Angeles California, so I suspect no cold weather issue.

Are you all saying that since my tire diameter is larger than stock, the odometer is under-reporting how far I am driving?

I'm still looking for someone to provide the location of the MAF sensor so I can clean it. Otherwise, I may opt to have it replaced.

One other thing, the engine light was on when I purchased the truck, so I had the oxygen sensor and the catalytic converter replaced. The mileage did not change after those fixes. Does that add anything to the discussion?

 

My local shop showed me the location of the sensor. Its at the end of the air intake hose, near the filter. It was very easy to remove and clean. I'll report back after putting high octane gas in.

Any other things to consider to increase MPG?

Thanks again.

 

I set the tire pressure to 50psi at the recommendation of my local shop. The tank I have now is low octane. I will switch to high next tank.

 

Hell yes. With 255x60x16 my odo said I got 550-600kms per tank. Now with the 265x75x16 it says I get 460-500ishkms per tank.

 

What size tires? And what load rating are the tires (C,D,E)??

 

The tires are Toyo A/T (285/75/16). I don't know the load ratings. I assume that such big tires also create more friction compared to stock tires.

I have an additional quesiton about octane. According to Consumer Reports, high octane gas is unnecessary unless there is knocking. I'm not getting any knocking using low octaine gas. I also heard from a tune shop that using low octaine gas in the Tacoma with the supercharger may reduce mileage because the computer senses the low octane and downgrades performance to compensate. Can someone confirm this and perhaps provide some authority for it? Thanks.

UPDATE: I think I found the answer to the octane question here: http://www.superchargersonline.com/content.asp?ID=104

 

Those tires are probably D rated, so the size and extra weight is working against your mpg also.
When you are ready to purchase new tires look for a P rated tire, that would help slightly (1-2mpg).
I find that keeping the speed no higher than 65mph, rpms around 2k, gets a little better mileage then just driving it however I want.

 

So at this point, would it be worth my money to go to a "performance tune shop" or wait to see if the mileage resolves itself?

The seller of my truck said that the truck was tuned for off roading but that it could be tuned for city/highway instead. I went to a shop called Dirty Parts in Culver City CA and they said that there was nothing to tune because the computer took care of everything.

Can someone help me revolve whether the supercharger can be tuned?

 

I finished my first tank. It was 87 octane. About half city half highway. The mileage was 17mpg. I assume that is pretty good and better than I expected. EDIT: my mpg is above 18 because of the discrepancy between what the odometer reads and actual distance traveled due to larger than stock tires.

I filled the tank with 91 octane and will report back if that changes anything.

Thanks again.