Hello all, I have this weird symptom coming from the bird. After I drove the car from repairing the deteriorated evap system, I noticed a weird sound coming from the engine. Every time I accelerate follow by a release of the gas pedal a "thump" sound can be heard after the rpms rev down... It's not loud but you can hear it when the radio is off. It's not a surge or a bucking feeling fyi. Any help resolving this issue would be great.