Had the same problem. The bolts had come loose from the intake flange to the head. Check the bolts are tight and the gasket is good. If not, take the bolts out and put some blue Locktite on the threads before reinstalling them.
Thank you for the help. The plugs and air filter were fine. The throttle cable adjustment did the trick, it had become loose underneath the rubber sleeve. What do the contact points inside the throttle mechanism control? The engine is very sensitive to the connection breaking contact before any increase in RPM occurs or the check engine light will come on. When decelerating, it seems like a very fine line for those contacts to close at the right time or else you get backfires. Thanks again.
My 2012 still backfires every now and again under certain conditions. Mainly when I abruptly let off the throttle going down hill. Already adjusted the throttle cable, I figure it'll work itself out once I get some more hours on it. It's barely broken in as it is.
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