bangs and pops you shouldnt get any, bangs and pops are unburned fuel igniting in the exhaust, this is either a rich mixture (which may be vtec mode as it does richen mixture for vtec) or ignition, the first is most likely. my bet is the airfilter for crappy mpg - try putting the other filter in and try it (just for my satisfaction) 
have you ever had a terra clean done on your car ????skinny wrote:Yep, on a standard pfi engine, the injectors spray fuel on the back of the intake valve, and the shitty bits in fuel cause gums and lacquers that build up to form deposits on the relatively cool surface. The recirculation of crankcase (oil) vapours also contribute massively to deposits.
IVD's is a very common acronym in engine design - stands for inlet valve deposits
The gas speed as it exits the combustion chamber is much higher than intake so nothing is hanging around to cling to the back of the valve, and also the exhaust valve is so much hotter its much more difficult to get deposits to format on it as they immediately burn off.
