[185kts]

I'm new to the Insght world having just bought a 2000 5 speed with 134K miles on it. So far I love the car! I drive 150 miles a day and I am getting 70+ mpg. I have been really trying to hold my right foot steady at a given MPG level and I have noticed that for some reason while holding the throttle very steady I feel a "surge" and the MPG either goes up or down about 10-15MPG. It almost feels like the A/C compressor is cycling on and off but I have it turned off. Could this be the engine going in and out of lean burn? If so, how can I keep it in lean burn or why does it go back and forth? Many thanks!!

 

[hawkGT647]

Yep, you figured it out.

Kinda cool when you first experience it, huh?

The surge is caused by the engine's ECM calling for a richer mixture (purge cycle) to clear the catalytic converter of nitrous oxides.

The only way to control lean burn is to dance on the accelerator pedal as soon as you feel and see a purge cycle kicking in.

Or just let it do it's thing, it's not that much of a hit to mileage.

Regards,