Sorry for the confusion on this thread but Edward T did ask me to post the info although it did not pertain to the truck in question. If ever you have this problem with the "TB45", it will blow the clip on cap off the air filter housing. This provides plenty of oxygen for the filter to continue to burn. The plastic housing may also melt and burn if not extinguished. It may get a bit messy. Worse than the mess, until I discovered the service bulletin, this backfire was really kicking my butt. If you go to Service publication there are photos.