A few months after I replaced my stock air box with a K&N cone filter I started having problems with my cars idle. MY 98 Avenger with the 2.0 would idle at 1100 instead of the normal 850 and when the air was on the RPM's would hunt between 1100-1700. I had a few different garages look at it and one shop charged me nearly $100 to change the throttle body gasket and clear my engine codes. Everytime the computer was reset the car would run fine for a day or so then the problem would come back. I was told it was everything from the throttle body to almost every other sensor and even my computer. I decided to put the stock air box back on and it has ran smooth ever since. I was almost to the point of trading it in but now that it has gone over the 150K mile mark I have decided to hang on to her for a little longer. Has anyone else ever had problems with a K&N product? Would it be worth trying a drop in K&N filter?

 

so did you just pull the box off and slide on a filter, or was it a CAI? with my first CAI i had a leak around the throttlw body, and since that was downstreat of my MAFS, i had unmetered air going into my engine, and it was causing a very lean condition...and it kept fouling plugs...once i got my new intake..it fixed me right up.

 

thats weird, but yeah unless you have a leak somewhere thats all i can think of.