Volvo 740 Turbo: Surging idle problem

mikeyguy

I recently purchase a 740 turbo which came with excellent records of repair and maintenance provide by a qualified Volvo mechanic. Many items have been replaced by the previous owner such as: the turbo, a/c compressor, water pump, radiator, brakes, etc. It currently has approximately 186,000 miles and runs great... except the idle keeps on surging even with the a/c off. This surging is a gently action, not a up and down type of surging. In addition when I first start the car in the morning, it will stall a couple times before reaching it's proper temperature. Also when I am driving with the cruise control on, I notice a little surging in the engine which becomes annoying on a long road trip. It is due for a tune-up and maybe this is where the problem lies. Any advice would be greatly appreciated.

Mr_Shiftright

You might check for a vacuum leak somewhere. This is a helluva lot of miles on a car, and at this point in its life you have to start considering pretty weird things. I don't think a tune up is going to solve the problem. It will require some careful diagnostic.

If not a vacuum leak of some kind, you have to trace whatever device controls idle speed by sending input to the computer....some valve or sensor does this, but right off hand, I don't know the system on this particular car.

Tighten all vacuum lines and test for leaks before you start spending money.