For a smooth idle you need to have all of the cylinders balanced very close to each other. That means compression, spark plug gap, valve adjustment, injectors, etc. After you are sure all of the mechanical parts are good then you can begin to attack the control systems. Rule out vacuum leaks, timming, bad ignition wires. On the injectors it is not so much a plugged up on as it is a dirty one. Dirt will cause a bad spray pattern and low holding pressure. They will have to be removed and tested to make sure they aren't the problem. David Teitelbaum vin 10757 --- In dmcnews@xxxx, "Payne" <bpayne@xxxx> wrote: > My car has developed a rough idle that has been most annoying. It sits > around 850 RPMs, and I know my idle speed motor is working. When it's at > this engine speed, it almost sounds like a distant helicopter. By that I'm > assuming it's not firing correctly on one cylinder at idle. It doesn't feel > like a completely dead cylinder, as when I'm driving it has all the power it > used to. I can rev it up and the engine sounds very smooth and quiet. > > The injectors open by pressure, correct? Hypothetically, if I had a > partially clogged one, would the pressure put through it at idle be low > enough so it wouldn't open? I heard a while back of someone having this > same problem. I do have all new plugs and wires, so my next area to look is > the fuel system. The car feels great on the road, I just wish the idle > wasn't so shaky. > > Thank you all! > > payne