Sherpa

My fuel economy has taken a nosedive in the past several weeks. I can attribute some of it to driving, but certainly not all of it. There doesn't seem to be a significant power loss, it starts and idles just like normal as well.

If the O2 sensor is bad, will there be any symptoms other than fuel consumption? Would worn-out spark plugs possibly be to blame?

I really shouldn't be getting 13 mpg....

Thanks for the suggestions.

-Scott

Brendan

o2, spark plugs, air filter, fuel injector cleaner

jacksonpt

I'm in the same boat as you... so this is a great thread for me. I'll keep my eye on it.

Toyota Punk

I think it's just the time of year. I'm down to 13-14mpg where as before the temps dropped I was getting 17-18. I cleaned the MAF and air filter mid-fall so I know it's not those.

Bob_98SR5

guys,

i had that same problem too. the problem became worse after i changed tire sizes from 31s to 32s. i would routinely get around 19 mpg and that dropped to 16. yes, i checked against my gps (sold since then) and the mileage. also, i always get worse mileage in the winter and as you know, a so cal winter is a like a sunny day in hell compared to NY winters.

now i get around 17 to 17.5 mpg. this is what i did to correct it:

- slowed waaaay down. i drive like my mom now (w/o the erratic use of the gas pedal, turning w/o signaling, etc)
- changed the spark plug and spark plug wires
- cleaned out throttle body
- cleaned MAF
- changed the PCV
- put more air in all tires (around 38 psi)

so in short, i'm not back up to 19mpg but i'm still happy i made some gains.

bob

MTL_4runner

Bob has some good info for you on his list of stuff to do. You could try replacing the O2 sensor as well but I would wait (replace in summer if all else has failed on the list). Up here the mileage drops dramatically when it is very cold (I go from 18-19 down to about 15-16 in -20 weather). The air becomes very dense and parts are cooler than they would be otherwise (lubrication in general is not as good because they never totally warm up).

Sherpa

It is nice to know I am not the only one out there experiencing this. I think Louisville, KY uses reformulated gasoline in the winter, which has the result of lower mpg, but that change usually happens in early Autumn.

I probably need to check my lubricant levels in everything, even though I have never seen a leak.

I think having everything cold-soaked does make a difference, but I'm just not happy with an approximate 20% decline in fuel economy.

How often do you guys change your spark plugs?

Does the V6 engine have adjustable valves, or non-adjustable? What would a tune-up really entail?

Thanks for the replies!

-S

MTL_4runner

Yes, the winter gas formula definately doesn't help either!

Tune up would entail:
Air filter
Fuel filter
OEM plugs
clean throttle body
clean MAF sensor

Other items that may help:
grease chassis (I also like to grease the driveshafts.....don't overfill driveshafts)
Valves have shims, but are very difficult to do! (I would advise not to)

Sherpa

Well, things seem to be getting worse. I have approximately 1/2 a tank of fuel now, and have gone less than 95 miles since fillup. Ouch!

Fuel prices jumped up over 30 cents per gallon yesterday, bringing premium fuel to $1.96/gallon. That makes the terrible fuel mileage even worse!

This weekend I might pull the spark plugs, and might even clean the MAF. I also need to check my tire pressure, which I know is lower than I run it in the summertime, but probably not that bad. (I'm guessing around 32-34 psi.)

I just thought I'd share the current events. The saga continues....

-Scott

MTL_4runner

I will be curious what does end up making a difference.

Sherpa

So will I!!!

-S

grafix43

how exactly would i go about cleaning the throttle body and maf sensor... i dont even know where the maf sensor is, and do i need to compltetly remove the throttle body in order to clean it right or can i just do it with it on. oh by the way i have a 94 pickup with the 22re. thanks - steve

instigator

sherpa did you get this fixed? i have what looks like the same problem. i just got 96 miles out of a 1/3 tank (this is w/ a very topped off tank) i usually get around 90 from the first 1/4 at top off. no engine MIL yet no leaking at the tank or anywhere else for that matter.