I'm fairly new to this site so I'm not too sure if this has already been talked about but a few months ago I swapped my h23 for an h22 and had headers with a flexpipe put in when I picked the car up from the garage I accelerated it and, what sounded to me like the flexpipe, was popping. The loud popping sounds stopped after a couple of days then I took it for inspection and they said I had a leak in the exhaust. I then took it to two mechanics who told me there were no leaks but one guy said the motor was weak. The motor was actually very strong while the car was popping but as soon as the popping sound stopped the car wasn't pulling as hard. It feels like an exhaust leak like the lady at the DMV said but the two mechanics said they couldn't find any leak. What is wrong? I changed the spark plugs and there is ONE spark plug wire that is taped up with electric tape but I don't know that would cause a weak engine. Any help will be appreciated.