CAI installed now instant fuel economy not working

[Bigmarsh]

Just installed a K&N cold air intake, no problems with the install but when i went to see my INSTANT FUEL ECONOMY i noticed it was working backwards...when i accelerated it went up when i eased off the throttle it went down. This was totally opposite to the way it was when it was stock. I'm very confused could someone please help.

[DmaxMaverick]

Welcome aboard!

That's right, if it's calculating gallons per mile. Otherwise, backwards as you said.

Verify the MAF is connected, and the SES lamp isn't on. If either, it could cause havoc with the computer. Also retrace your steps during the intake install, checking everything that might have been disturbed.

If everything checks out, try a computer reset. Disconnect both batteries and ground a positive terminal end (CABLE to chassis, NOT the battery). Reconnect after 30 minutes and try again. This should reset the computers to default, and clear any codes, including soft codes (stored, but no SES lamp). Often, some emission codes will set, but not display the SES until the condition is repeated a number of events over a period of time, or warm-up cycles. Poor MAF communication, fouling or damage will cause emission codes. K&N wetted gauze air filter often cause MAF errors, due to oil fouling. Some aftermarket intake systems can cause MAF faults, due to a change in air routing, and this can cause MAF errors. Often, resetting the computer will force a relearn of the MAF values, and correct the problem, if the MAF is otherwise reading correctly.