My EA82 wagon has a slight, random misfire. Recently, I've been pretty determined to find the solution.
About 20,000 miles ago, I swapped the long block. Used my old distributor, but got new spark plugs (NGK BPR6ES-11), new spark plug wires (Import Direct 40975), new distributor cap (Import Direct 10-0199), and distributor rotor (Import Direct 12-0186). All parts I got from O'Reilly Auto Parts. Before starting the engine when I installed it, I accidentally hydrolocked it with coolant. I pulled the plugs and cleaned out the coolant. I also accidentally had two of the spark plug wires mixed up. But once I got it all sorted out, I was driving fine. This is when I first noticed the slight misfire.
Flash forward to today: I've currently got new plugs (NGK BPR6EY-11) and new wires (NGK 9350) coming in the mail. My current spark plugs don't look abnormal. I think having NGK wires will make a big difference, but I have another issue. My distributor rotor seems to be making serious contact with the cap.
There's virtually no up-and-down play in the shaft, nor side-to-side. There's some rotational play, but since it's supposed to be spinning, I don't see how that could cause it to do this. Could it be the wrong parts? What have you guys used for your cap & rotor?
I figure what I'll do is grab another distributor from the junkyard. Get a new cap and rotor as well. Besides shaft play, how can I tell how good the distributor is? Is there a way to clean it once I get it home? I have a good feeling that this is what's causing my misfire, since my misfire seems to be very random. It's not necessarily on one cylinder, and it misfires at random times (once every 1-5 seconds).