well ive just done a few bits to the car including oil and filter change,new spark plugs and fitted a second hand aftermarket exhaust and now ive got a lumpy idle and a hesitant acceleration.what do you think could be the problem.could it be the exhaust baffles have burned out or is it more likly to be the plugs or filter.it was an afi filter which fits fine but is bigger than an oem filter.any ideas cheers