Just 1 month ago I replaced 4 of 5 plugs and the battery in my 84 300sd. This morning it was a bit slow cranking and no start. Hooked to jumpers, still no start. Start ohm testing plugs and all the new plugs give wacky readings. Most read infinate resistance.
So, is there a scenerio where something can be wrong with the car that screws up the plugs? or is the meter bad. The meter is only 1month old also but it could be suspect cuz it is the Harbor Freight el cheapo. When it is set on 200 you will get .2 reading just from touching the leads together.

Eric Z

PS while installing stereo a few weeks ago I found a wiring harness under the passenger floor carpet that was unplugged. Plugged it back in and fuses pop so I left it unplugged. Could this be related? what does that harness do?