car surges at start and at other times over revs.

"You need to inspect all rubber hoses to include the air inlet hose prior to the intake manifold, you have the right idea but even a repair shop will need to do a visual inspection, its common that they get old, dry and crack, get rub marks to the point of leaking air and burnt from hot exhaust, etc.

You can spray carb cleaner around to find a leak, some mechanics spray some water around to find a leak but don’t go overboard. All knowing that your problem may not be an air leak but this is the best step to start inspecting if you don’t have a scan tool."

Jettas are notorious for a lot of minor engine problems, and the part that causes the majority of these minor malfunctions is partly caused by the Distributor Cap. It is a simple fix and you will be surprised by how much better your car will run, or even start up with this small fix. Make sure your engine is not hot when you perform this fix. Open the hood of the car and locate the Distributor and then follow this video. As for the idle try giving the timing a little twist in either direction . it is a wire cord that is attached to the gas pedal, when you press the gas it pulls the arm of this lever like part. on it there is a small screw, with motor running, get a screwdriver, and with it, gently move the screw in either direction until the car is idling at the strength/ speed that feels right to you https://www.youtube.com/watchv=ticvd7ZKc...