Ok,thats good.Did they change the fuel filter?. It's under the car beside the back axle.
Idle 1000 RPM in nuetral?. In drive ,with air con running it should be around 700RPM.
Air by pass is in the front of the engine intake manifold where there is a large while(ish) plastic slotted head screw. this is the adjustor for idle speed.
If it's idling at 1000 RPM when hot,it's not a by pass problem.

Was the ignition timing checked?
Before doing anythng else I would suggest you change the fuel filter and change the ignition coil. If it's the original,which it probably is,it's beyond it's "useby date".