Expert: Sean Halliday - 8/15/2010

Question
my 1991 olds cutlass ciera runs rough. it idles high and then low and will stall if i dont keep on the gas. I have changed plugs, wires, mass air flow, fuel regulator.  Last year I had a test on the coils and he said they were fine.  what else could it be?

Answer
This model has an egr valve which may need either cleaned or replaced.The 92 model had this problem also.Check for vacuum leaks especially around the intake manifold.Spray some carb cleaner at the intake and watch for any change in rpms.If the idle changes you have a leak.