Another rough idle/miss thread

[86cucv]

I just picked up my 95 PSD yesterday and I noticed that when it is cold or in neutral/park it has an idle rough enough to shake the truck a bit. After doing some research I found a few things that it could be:

Injector wiring
Injector O-rings
MAP sensor
Using too thick of an oil

Tonight I tried unplugging the MAP sensor and I found that the truck idles exactly the same with it unplugged, is this normal, can anyone verify this? Also, I read that using lucas is bad for these motors and can cause a rough idle. Apparently the previous owner used lucas and Shell Rotella T in the truck. Right now it is about 27 degrees outside, so that is probably wayyy too thick for the motor. I don't have time right now to pop off the valve covers to check the injectors, but are there any other suggestions on how to troubleshoot this issue?

One more note, this truck doesn't smoke at all. It doesn't smoke when it starts, when it is warm or when I am romping on it. Would that be indicitive of a bad MAP sensor? I'm not sure if it would run lean or not....