Chevrolet: Engine noise, chevy garage, pain in the butt

Question
Hey Roger,
I have a '89 Camaro with a 2.8 V-6, A/T. At idle(hot or cold) there is a light knock/rattle that can only be heard from inside the car. It seems to be from the firewall area. The crankshaft and bearings have been miked by the local Chevy garage and are within specs. Oil pressure is about 35 lbs at idle. The noise goes away above 700 RPMs. This noise has lasted 15,000 miles so far. Any advice?

Answer
ED;
 Knock- some noises are such a pain in the butt, it could be a lot of things, have you gone under the car when running to see where it could be comming from. It could be in the motor-oil pump or in the tranny. I would get a long rod that you can place down where you think it is comming from and place the other end to your ear, this way you can tell much more where the sound is at. check the motor mounts , ex. system     ok