I just changed out the spark plugs with Mercedes Benz spark plugs sourced from Gerry (thank you). Unfortunately car didn't run right after I changed the plugs. Looking at my extensive maintenance records I see no evidence of ignition wire change. Other photos on this site confirm I am still on the original ignition wires. Spark plugs were last changed at 91,000 miles in 2001 (146,000 on car now).
Spark plug wire resistance check
1: 8.1 kOhm
2: 2.3 kOhm
3: 2.19 kOhm
4: 2.18 kOhm
5: 2.23 kOhm
6: 2.25 kOhm
7: 2.26 kOhm
8: 2.13 kohl
Hmm... I wonder what the problem is? I think handling my original wires send #1 over the edge. I just ordered a new Bosch spark plug wire set and hopefully that will cure the problem. Rotors and Caps were changed 9 months ago at 142,000 miles by previous owner but they didn't bother with the wires.
Anybody have a tip on how to remove and replace the wire going to the coil that appears to be under the ABS control pump? That is one tight fit.