940 GL Non-Turbo

I posted my problem about getting very rough idling in the morning especially a few seconds after the engine is turned on. Occassionally, at traffic stop the car would rock slightly with lower RPM but this is intermittently.

Steve Ringlee suggested that I put in a bottle or two of techron. I did that and the next morning the poor idling was visibly improved. After the third day, the poor idling came back.

When I put in the techron, it was with a full tank. After the third day, the tank was slighly above the half way mark. Is it possible that the poor idling is due to a faulty (or near faulty) fuel pump?

I tested the resistance of the plug wires with a ohm meter because one was apparently loose on contact, and here are the results:

2 wires have infinity ohm. (my meter was not able to get a reading)
1 wire read at 19450 ohm
1 wire at 1460 ohm

Although I do not know what is the proper range of resistance plug wires should have but I am certain there is something not right with the wires reading I've got.

Question is can these readings give poor idling and bad fuel consumption?
When I remove the plug wires one by one with the enging running, the idling got worse when either one is pulled out. So does this mean the wires are okay?
This is very puzzling, Can anyone help?

Thanks

Laozong