Bad milage

[AvroAero]

Hey,
I got a 99 4.6L with a K&N FIPK, Gibson headers, Gibson catback exhaust, and super chips program. I get such shit city millage, 10mpg. My highway is up to 19, usually 18 or so. Is there any reason city would be so crap?

 

[green03]

yeah, shift points in town that can only be fixed by a custom tune...... You are always in a gear too high at slow speeds.....

Matt R