The intake manifold gasket can fail causing vacuum a leak and/or a rough idle condition. Replacement of the leaking gasket will be necessary to correct this concern.
Car Problem Reports
Mazda 626 Intake Manifold Vacuum Leak Causing Rough Idle
Mazda 626 Problem
Engines Affected: 2.0L 4 Cylinder, 2.5L V6
Average Mileage: 124,559 mi (98,000 mi - 150,678 mi)
Car idles roughly while sitting at lights and in park. The rpm's on the vehicle are very low as well.
Visitor, 2000 Mazda 626, 2.5L V6, 125,000 mi
Whenever I sit at a light, in traffic or through a drive-thru my car shakes and makes a bit of noise. I took it to a repair show and was told I have an exhaust leak.
Visitor, 2000 Mazda 626, 2.5L V6, 150,678 mi
Car is all of a sudden riding ruff. If car is in park and on the speedometer moves from 0 to 20 mph. And finally feels as though transmission is slipping.