Can someone help me identify what this is?
I have an engine that recently has started doing this. It hesitates almost as if it doesn't want to turn on due to no air pressure or something. It only happens within the first minute of start up. At times it backfires and makes a minor popping in the exhaust almost as if it struggles to breathe even though it has a new filter and has good air ventilation. Not only it hesitates but it also makes this weird knocking noise inside the engine and I can't seem to figure out exactly what it is. It goes away after a minute once it warms up and it doesn't seem to do it anymore. Once it's warmed up it drives just fine with no problems, it's only the first minute within start up. Can one of you guys identify what is wrong with it?