Huge Drop in MPG
Thread Starter
Joined: Jun 2010
Posts: 10
From: Michigan
Huge Drop in MPG
Well about 10 days ago I put a KN cold air kit the PKII or whatever on my 04 4.6 GT and since then the MPG has been about cut in half. Thats the only modifications I have as of now. The car has about 26k miles it say an aweful lot and im just now driving it somewhat consistently. The last tank of premium I got about 160 to the tank well from full to just below a quarter. I cannot notice any leaks in the air system all clamps and hoses are tight. I have no idea what would have brought this problem on? Any help?
4.6L Section Moderator
Joined: Nov 2007
Posts: 10,286
From: South Central PA
What I suggest is taking some starter fluid and spraying all the spots on the intake tract that might be leaking. if you notice a change in idle speed, i would suggest that you address that. Could also try changing the fuel filter. I know that has nothing to do with your new intake but could be the cause and it just happened right around when you put your intake on.
Joined: Jun 2010
Posts: 8
From: MA
First I must ask if there is a reason you are putting premium gasoline in a car designed for 87 octane, did you get it tuned for premium? Also frequently the k&n filters can come from the factory with too much oil on them so your MAF may need some cleaning. Last thing I would ask is, did you reset the computer when installing the CAI? If not this could also be a factor.
4th Gear Member
Joined: Apr 2008
Posts: 1,546
From: Nebraska