A few months ago when I went to the bulk yard, I was backing into the driveway and noticed the truck acting weird. Gave it a little gas, it would go backwards, let off the gas and acted like bearing flat spots and you could hear the driveline chattering as the truck slowly rolled to a stop. That's the best way to explain it. In Drive there was no flat spot feeling. This past weekend I took it out for a drive and it backed up fine for the first day. THEN, it began running like crap, really bad. It felt like the tires were all out of balance. I found three vacuum leaks, each from rotted vacuum port plugs. When I rebuilt the carb a couple years ago I went with electric choke because vortec heads don't have provisions for the warm air choke. Found some fresh plugs that fit, no more vacuum leaks, and also replaced the in-line fuel filter. It still ran like crap. Forgot about the in-carb filter, replaced that and it now runs a little better. However, sometimes when I put it in neutral it wants to creep forward, other times it doesn't. Also, sometimes there is no stumbling from a stop, and other times you can hear it trying to take off, but it stumbles and goes, stumbles and goes. Would a weak spring on the power piston be an issue with partial throttle? I suspect I may have some bad juju in the carb from it being gunked up from not running in a long time, so I've been running Motor-Purr in the tank to clean things up. It fires right up, just a tap of the key like it's always been, it just doesn't run as good as it should and I am running out of ideas. Dumb question...do you guys think the shifter rod is out of adjustment? Or can a vacuum leak cause some of these weird going forward in neutral things to happen? When everything is running like it's supposed to truck is a blast to drive, it'll take off quickly, shift normal, and run smooth. Then it does its stumble and go thing and loses a lot of power but you can feel it gain it and lose it, gain it and lose it. Any suggestions on what to look for will be greatly appreciated. Thanks.