Just discovered a problem that was causing my engine warm up poorly...idle unevenly and start hard when in rainy conditions. For a long time I had accepted these problems as just due to high mileage....figured it needed a major carb overhaul, or some expensive emissions work. A week ago I tried to start my engine after several rainy days of sitting. It took me about five minutes to get it started and it ran very rough for most of the drive. It finally dawned on me....moisture in the distributor !....next day I pulled off the distributor cap and found that the distributor O ring (which was 275K old) was hardened and cracked in several places. Its supposed to be rubbery, not hard like plastic. Replaced it for $ 8 and that alone seems to have cured all of the aforementioned problems. It's probably the easiest fix I've ever come across on this car, and a good troubleshooting step for any car with a distributor.

 

Good advice! If you find that the dist. cap has moisture in it and time doesn't permit the repair described above, spray the interior of the cap with WD40. It will displace the moisture and allow the car to start until the proper repair can be done.