Air tool oil, WD40, vasoline, etc are all possibilities, but to resolve the motor permanently for performance, go with a rebuild. It's well worth the money IMHO
Also, check the hoses. I saw a leaky hose that was undetected and it behaved like a tired motor, when all along the problem was just the hose! Vacuum hose is a cheap way to make sure you are all tight.
Double action fuel pump will keep constant vacuum for sure, but it's a RPITA to plumb up neatly.
My two cents are: RainX frequently and rebuild the motor.
I'm a strong supporter of RainX and I actually don't even turn my wiper on at all anymore and would rather polish up the glass when I know I'm running in rain. If your truck is a daily driver, then a rebuild would be a starting point. If it's a weekend driver, I think you'd be surprised how well RainX works.
In addition, RainX Anti-Fog is excellent on the interior windshield. It will keep those windows from fogging now matter how much breath you throw at them and how much moisture is getting in the cab.
