I installed the K N intake and ran into problems with stripping a screw; now with the stock unit back on there were very noticeable vibrations transferring from the engine--to doors when opened driver seat especially leg area. this happens only at idle when rpms come down. in other words turn it on, and in a few moments lots of pulsation/vibration in cabin! why does this happen? only thing I can think is that something got messed up with MAF or the connector to the MAF--I didn't drop the MAF or...