I've tried the solder repair on my wife's 94 model 940 with no success.
I was able to reflow the solder with no problem but the problem is apparently somewhere else.
She has to tap on the fuel gage with the end of her hair brush to get it to work.
It will drop at random.

You should try the solder repair.
It's not difficult if you have a small pen type solder iron.
The #1 rule to soldering is to allow time for the solder iron to reach full temperature before soldering.
The #2 Rule is to know when good enough is good enough...aka....knowing when to quit.
Flow it once then stop.

Just my opinion
steve