Two weeks ago I started up old reliable, but it ran rough. I thought it would smooth out as I ran it, but it did not. I checked my codes. 1-1-1. So then I carefully checked all the vacuum lines. No leaks as far as I could tell. The engine at idle rocks back and forth on its mounts almost as if one cylinder isn't firing. All kinds of scenarious present themselves, from damaged plug, broken spark plug wire, etc., but aside from worn plugs, distributor cap and rotor needing changing, nothing I've checked could account for a sudden miss like one cylinder gone. Any suggestions, anyone? Dick

Mine has done that previously. It's been a crack in the distributor cap with a little bit of moisture inside. You can isolate which cylinder it is by pulling plug wire at a time while it's running and listening for which one does not make a difference in the idle. Then you may be able to switch wires, plugs and see if the problem follows. But, if you haven't already done so, I would go ahead and replace plugs, cap, and rotor.

It sounds like you realize the plugs, distributor cap and rotor need to be replaced. Any or all of those could be the cause. Why not replace them and see if in fact it fixes the problem??

Randy

Could be a dirty or clogged fuel injector. Click here for information on cleaning and testing the injectors.

Click here for a vacuum leak diagnosis.

Check your spark plugs. Does one look as though it has been 'steam cleaned' ? If you, you possibly have a bad headgasket.

Have you cleaned the flame trap and Idle Air Control valve (motor) lately? Take it out, clean the inside and check that it is operating. You might check the motor mounts they could be broken. Dan