my car seems to be leaking oil from underneath the engine. i thought maybe its just an oil pump seal. they ran some tests and now tell me that i have a misfire on cylinders 2,4. all i have moded is a turbo back exhaust and an aem intake. my car isnt under warranty so all the aftermarket parts are still on. my question is what the heck are the service guys doing and should i just go somewhere else to have someone look at it?