Ive been trying for months to improve my protege's fuel economy...my car is currently getting only about 18MPG and i know thats no where near what it should be...ive changed the o2 sensor...egr valve...distributor...i got a tune-up...fuel system cleaning...everything...is there something im missing???...if anyone can help me i would really appreciate it

 

I hear ya Mysteryman, why else have a 1.5L engine if not for an economy-miser, right? You definitely should be getting A LOT better than that but it depends on several factors. First, how do you drive (agressive, casual)? What is your typical driving on a tank (all city, a mix, a lot of highway)? Aggressive driving and city driving will greatly reduce fuel economy even on these little engines.

After considering that, do you have access to a scanner to read O2 sensor and fuel trim info? Or even emission test results. This will give an indication as to how the engine is running and where the problems may lie. Given the things you have already done, I would certainly test the fuel pressure.......2 years ago my pressure regulator went and resulted in 92psi and much less fuel economy. For the most part, you wouldn't know it by the way the car was running though. Also check the plugs to see what they look like and get an idea if the engine is running rich or lean.

How much mileage is on the car? Checking compression might be a wise idea as well......low compression will never yield peak efficiency.

hope this helps.