Installed K&N CAI, was getting 19 MPG, now getting 16.8 MPG.

Is this normal? I figured the mileage would go up, not down...could I have another problem??? And no, the problem is not my right foot.

 

do you have the GT or V6? Also it will take about 200 miles before the computer will make any adjustments. Since you are pulling in more air the computer is adding more fuel to compensate. Disconnect your battery for 5 minutes and then reconnect it.

 

the car is a GT.

I disconnected the cable during the installation - about an hour -- should I do it again?

Has anyone else had mileage suffer over 10% from a CAI? I was expecting the opposite -- a 10% increase (wishful thinking).

 

give it time, the computer needs to relearn the intake, trust me, those numbers will go up shortly!

 

Make sure you double check all the clamps to be sure its all tight. My last road trip i was crusing at 75 mph getting 25 mpg.

 

my gas mileage wasn't great either until one day I started getting 28 mpg! The computer needs to adjust, give it a few weeks

 

When I first installed the K&N my mileage went down also but it came back after the computer adjusted. If I remember correctly, I think it was around a 3 mpg loss initially. When I went to a tune, same thing happend.
Give it time.

 

Mine went way down right afterwards between the computer relearn and my new leadfoot issue.

It is starting to come back to normal now after about a week's worth of driving.

 

I had disconnected my battery a couple weeks ago without making any performance modifications, and I had a similar decrease in gas mileage for a bit. The first tank of gas was down to about 16 MPG, and 225-250 miles later on the next tank of gas, I was back into the 19.0-20.5 range, so give the car a week to relearn and see if the problem corrects itself!

 

Sounds like it needs time to relearn, anyone's mpg ever permanently stay down? Have heard that yet so no big deal I guess.

 

Mine also bounced back after a few tanks of gas. My mods (listed below) were all done at once. I dropped from above 20 mpg down to 16-17ish in mixed driving in the butt-ugly traffic around here. I'm back to over 19 in mostly pleasure driving. With just the few mods I performed, the car is perfectly suited for the one thing I bought it for: Fun! I don't care how much gas she eats.