I have just performed the poor man mod to air intake by removing the air intake shroud at the fender and running my K&N in the open. I'm still using the stock intake from the filter to the carb. I also just had my plugs changed. Now on a couple of occassions in the last two days my truck has backfire through the carb when I get it up to about 70mph. The first time it did it my check engine light went crazy, it was blinking on and off like a flasher. Am I getting to much air into my intake?