Last weekend I replaced the stock air filter with a K&N replacement filter. The filter came pre-oiled and after a day or so of driving, I noticed a slight vibration in the gas pedal as well as the engine seems to be more peppy and rumble a little more, all at lower speeds (under 40 mph).

I mentioned this to a guy today at Off Road Warehouse when I was picking up some stuff and he said that some of the oil from the new air filter is coming off and covering the thermometer, making the engine think that it is cooler than it really is. Since the engine thinks it's too cold, it uses a little more gas than normal to heat itself up.

Anyone ever heard of this happening or had similar occurrences?

 

I had no issues when I dropped a K&N into my '07. I know you need to be careful not to over- oil following a cleaning, but I personally have not heard that explanation before.

 

I've heard of the oil getting on the maf sensor on certain cars/trucks but never have heard of them effecting speed density cars. I guess it could be possible if the inlet temp senser is somewhere near the filter.