Decreased gas mileage, 2001 RAV4

I’ve owned a Toyota RAV4 since May 2001. I am the original owner & only driver.

All regular maintenance had been performed by a local Toyota dealership until recently.

Other than replacing the catalytic converter at 79000 miles, no major work has been done.

Gas mileage had been 30 to 33 mpg, in town. 30 to 37 mpg on the highway; varies with speed.

2/3 to 3/4 of the miles are stop & go, city.

I use the same regional chain for gasoline when available, & have done so for the past 3 months.

I live in a mild winter climate area, southern 1/2 of AZ.

3 weeks ago, I took my RAV4 to an independent repair shop, on the recommendation of a trusted friend.

Service performed:

Spark plugs changed to NG brand plugs. [ Spark plug change is recommended at 120K miles ].

Oil & coolant / antifreeze changed.

Filters changed: cabin air filter; engine air filter; engine oil filter.

Items cleaned: mass air flow meter; throttle plates.

Items inspected:

All fluids; drive belts, hoses, brakes, fuel lines, fuel cap, steering components, suspension components, suspension components, exterior lights, exhaust piping & mounts.

Brakes all 70%.

Onboard computer scanned for fault codes; none found.

Gas mileage is now 25 mpg.

Does this RAV4 have a carburetor?

Other than the possibilities of switch to a colder spark plug or improperly gapped spark plug, what should I tell the mechanic when I take my Toyota RAV4 back?

Thanks for your help.


5 speed standard transmission

2 WD

Gasoline powered

Tires rotated at time of maintenance, 3 weeks ago.

Check if they changed gas to winter blend, more ethenol sorry about the spelling.
When they do this milage goes down.

The one thing I don’t see on your list that could effect the fuel mileage is the thermostat. And on a vehicle with 79,000 miles on it it’s due for replacement if it’s never been done.

If the thermostat is stuck partially open, it takes longer for the engine to come up to full operating temperature if it ever does. And until the engine gets to operating temperature it uses more fuel.


No winter blend.


Mileage is 125,000. I apologize for the error of omission.