I recently installed one of those nice,expensive,washable K&N air filters in my 94 B4000. Ever since my idle lopes up & down. I would assume it's now getting to much air? Any one have this problem? Any one know a remedy besides throwing a regular cheap air filter back in and having no use for the nice new one? This is driving me nuts!! Any help greatly appreciated!

hi SoundElixer,
I had similar problem on my b4000 2002, some of the oil from the filter got on to the MAF sensor, i had to use intake clener to clean it. After that it run ok for 2 months, then i got the same problem. So i just cleaned MAF and installed regular filter from dealer, no problems since then...

yeah, the oil can cause problems with the MAF. also check to make sure you have the air cleaner box fully locked down. the latches on the side need to be snapped into place totally. if you can pick up on the upper portion of the box and it seperates then its not secured properly

Hence why K&N filters void the warranty.

Many people at the automtove school I went to used them without problems which many of their cars did have the current sensing MAF system in them like the B4000.

Almost all K&N filters I have seen other than from other students at school where over oiled. I would recommend vary carefully oiling it making more sure that it is even rather than having enough oil, let it sit a few hours, touch any white spots, let it sit over night then in the morning dab the pleats and around the rubber seal with a clean cloth and then install. Clean the MAF and try it for a while, if the loping comes back put the stock filter back in.