Getting bad gas mileage in my '99 Camry even after fixing it up?

[cameronfield]

All right guys, here's the deal - I've got a '99 Camry CE, 4 cylinder, 2.2L engine, etc. etc. When I first got the car, I was consistently getting 18 mpg in the city. So I did the following to try and improve that:

- New spark plugs/wires
- Fuel injector cleaner
- Octane booster
- K&N air filter
- Pumped my tires up to 44 PSI (sidewall max)
- Accelerated more slowly
- Used seafoam in gas tank, through PVC valve, and in oil

I'm up to about 22 mpg, but multiple people have told me that seems really low for a 4 cylinder Camry. Any ideas as to what else could be wrong? It runs fine, no stalling or stuttering, no check engine light, shifts smooth, etc.

I'm thinking it could be the o2 sensor(s), but I'm not sure. I'm considering taking it to my mechanic and having him check ($37 just to check). I dont want to end up spending $100+ if they're just dirty or something. What do ya'll think I should do? I'm running out of ideas :/.

[Brian R.]

Check your wheels and make sure they turn easily. One of your wheels may have a brake problem and dragging or binding (emergency brake?).

Check your compression.

Use NGK or Denso plugs only

Check your exhaust system for kinks or obstructions in the tubing or a crushed muffler or cat converter.

Check your valve timing - your timing belt may have jumped a tooth or two on one of your cam or crank sprockets.

Not likely to be your O2 sensor. You would get an error code and check engine light for that bad of performance. Your mileage is really bad for that vehicle.

[Ja2Mike]

What kind of mileage are you getting on the highway? It could be that nothing is wrong at all, it entirely depends on what kind of city driving youre doing.

If youre constantly stopping and going for the majority of the time youre driving, ofcourse youre going to be getting very low mileage.

It could also be the way you drive, heavy acceleration, excess speeding, leaving your car on during long stops (waiting for someone to come out of their house, etc.) can really hamper mileage. Look up for tips on how to increase mileage.

[Mike Gerber]

In addition to the items mentioned by Brian, check the engine coolant temperature sensor. It may be slightly out of range (not enough to throw a code yet) and showing a cooler engine temperature than is actually happening. This would cause a slightly rich fuel mixture, causing a drop in mileage. You will need a digital volt/ohmeter and the specs from any manual to do this. There is a geneartion 4 manual stickied at the top of this forum that is available for free downloading. Also, check that the car isn't running too cool. This would indicate a problem with the thermostat stuck in an open position. This would also cause an excessively rich fuel mixture. The gage on the dash should be at about the 11:30 position.

On future posts it would be helpfull to post the mileage on the car.

Mike