Help.
 

Alright, so ive got a 94' 3.4, i parked it, and when i got back in and started it i noticed something wasn't right, when accelerating there is a pulsation on the gas pedal, also the entire car has started to shake a little. The exhaust has gone from a constant growl to like a pulsating one, sounds almost like a harley. I'm taking it to my mechanic tomorrow, but i was wondering if anyone had any insight. Thanks.

how long has it sat>?

The day that it started it hadn't sat since i bought it, then it sat for a week, and I started driving it again, and same story, Could it just need a tune up?

Could need a tune up, could be a clogged cat