I just changed my airbox lid to the whisper lid and my gas mileage has been terrible. (13-15 MPG) in my 3800!! I dont rag it out any more than usual and yet its getting much worse than before. Is it just coincidence? or does the lack of a resonator have this effect? (wouldnt think so) It also has been getting hotter around here (95-100+) does that have any affect on gas mileage. I didnt think it was tune-up related just because the mileage dropped off so quickly. Any insight would be appreciated.

 

Notice anything wrong with how the car drives? Punch the throttle and see if its smoking any...


Is your SES light on? If so run it for codes.

 

No light, no smoke. If anything its actually running smoother in the higher RPMs, not sure if its from the air flow or not. I guess the simple way is just to change it back and see what happens.

 

Alot of slow speed with the AC on?

Mine's come and go this season, I got 19 last week at the shore with the AC on the hole way and 23.5 this week around town.

 

temperature will affect gas mileage a lot. i doubt the loss is from the whisper lid because if anything you should get better gas mileage from it since it is free flowing. less strain on the motor to suck air in.