Okay so I just got my first Mustang ever it's a 1998 GT. A lady was moving and it belonged to her husband who had died four years before but she said that he had just rebuilt the engine before he passed away. Anyhow so I can feel the problem that I'm going to describe in the gas pedal it feels like a bumping / grinding feeling at low RPMs and I almost would want to say that it was similar to like a rod knock because I just had a Buick that had a rod knock but if it doesn't have the sound though. Like that clack clack clack clack. I was able to feel that same feeling in the gas pedal of my Buick but now here I'm driving this new Mustang that I really don't know exactly what has been done to it. And I just want to try to troubleshoot this issue without having to go to a shop because my budget is little to none. Under the hood engines completely clean when I lift the hood and I throttle up I don't hear anything the engine sounds totally quiet so I was wondering would it be possibly a exhaust leak or transmission issue or something I mean has anybody else to experience this? really you can feel it in the gas pedal for sure as I accelerate the sound / feeling kind of goes away but then I always feel that that feeling whatever the hell that sounds like feeling is on the gas pedal. The oil looks clean I mean like I didn't do a oil change or anything just pulled the dipstick. didn't see any metal flakes or didn't look dirty or anything no milk and it smells all right. Any ideas should this be an issue where I just like park the car until I find out what it is so I don't hurt the motor