Glow Plugs test fine, but horrible start

[TurboDMercy]

I have an '82 300D with the OM617.

In the mornings I find myself cranking for 45-60 seconds (as the owners manual suggests). I just hold the key and let the starter go until she starts up. I thought I had bad glow plugs until I tested them with my multi-meter, all read .8 ohms. Once I finally get it started, it doesn't idle rough at all. All the forums I read point to this being the glowplugs still, and I'm wondering if my glowplugs can still be bad even though they all get the same reading of .8 ohms.

Thank you for all suggestions.