The price of gas seems to have stabilized here at $0.85 per litre. That is about $3.50 per US gallon. So it is worthwhile to try to improve mileage.

Apart from not having a heavy foot, towing or carrying heavy loads, roof racks, "riding" the brakes, proper tire inflation, good plugs and coil packs, here are a few tips and things to check if you want to be sure your EXPY is giving you the best it can or if you detect a sudden loss of fuel economy. They are not necessarily original with me, but things I have experienced or picked up through reading. Some may cause a check engine warning, others might not.

1. Mechanical problems such as exhaust restriction can result in a too-rich fuel mixture by causing a false MAP sensor signal;

2. Exhaust systems that reduce back pressure too much can fool the oxygen sensor and result in a rich fuel condition as well;

3. Poor fuel or incorrect octane rating cause poor acceleration, missing, etc.

4. Dirty air and fuel filters cause engine inefficiency;

5. Make certain the coolant mixture is right, the operating temperature, radiator cap holds the correct pressure and the vent tube is clear; (see next on coolant sensor)

6. A malfunctioning coolant sensor can result in a rich mixture, affect the timing, idle, cooling fans, canister purge, and EGR valve;

7. Improper timing due to worn timing belts;

8. A dirty oxygen sensor may be inaccurate and can lead to a too rich mixture;

9. A defective MAP sensor or vacuum restriction to the sensor can affect both fuel mixture and timing;

10. A contaminated air charge sensor can cause inaccurate adjustments to the fuel mixture;

11. Improper fuel pressure- too little gives a lean mixture, too much gives a rich mixture bother are bad for performance and economy;

12. A worn throttle sensor can cause incorrect fuel mixture, timing, torque converter control, emission control and AC clutch control;

13. Worn or dirty fuel injectors cause incorrect fuel mixtures.

I am not an expert mechanic and don’t really understand the ins and outs of all the sensors and computer adjustment systems, but it seems to me that any sensor that can affect fuel mixture or timing should be serviced at regular intervals. Also, a balancing of air intake and exhaust systems should be considered when doing modifications to such as adding K&N type filters or low restriction mufflers and pipes.

Any comments, additions, corrections?