I just bought a 1999 tacoma, xtra cab, 6cyl, automatic with 187,000 miles and 31" tires. It seems to idle and run fine but a little short on power maybe, the problem is Im getting 8 or 9 mpg and have no idea what the prob can be, any ideas?

 

I would start at the typical maintenance items if you don't know what the previous owner did or didn't do.
1. Check your air filter.
2. Oil change
3. Spark plugs - NGK or Denso only
4. Spark plug wires- NGK or denso
5. Make sure the tires are aired up to 32psi
6. Look and see if there is a sticker on the radiator or the front cover stating if the timing belt has been changed.
7. Time to buy a Haynes manual

 

A little short on horsepower compared to what??

Yes I must say my 3.4 is short on horsepower compared to a friends 400 plus horsepower Duramax diesel in his 3/4 ton pick up.

How much weight do you carry around in the truck?

What gears are in the truck??

What rpm do you see at 60mph ??

What kind of driving do you do city or a 100 mile high speed trip to work??

Are you in the mountains or flat lands

What kind of temperatures?

How much idle time??

All these things factor into the mileage you get.

 

Is your check engine light on? 8-9 mpg is not right. With a sc and a heavy foot the worst i've gotten is 14 mpg.

 

Fuel filter makes a big difference too