I have been having idling problems since it started to rain, the car ('94Z LT1)idles fine inside a garage or under a covered service station but as soon as it gets out in the rain (high humidity) it hardly stays running. I suspect it's probably the Opti. A more concerning issue is while looking under the hood in a darkened garage, the Header pipes on # 4 & 6 cylinders were glowing red.
I wonder if those injectors are failing and causing those cylinders to run too lean. Help.

 

Somebody on here recently had a glowing header problem. I think it turned out to be the opti. Do a search on "glowing header".

 

mine did this due to plugged injectors