I'm going to recount a tale illustrating the tire pressure issue. Stick with me on this.
Years ago a couple friends and I went out to get firewood in their 15 passenger cargo van. We loaded it up and started down the highway. Two lane country road with zero traffic, thank god, because that truck used up both lanes wandering side to side, twitching like a snake with its tail on fire.
Seriously. I'm not exaggerating at all. And that was at 40 mph.
Having some experience in the matter, I asked what tire pressures they were running: they had no idea, having never checked since they bought the truck years ago.
I made 'em pull in at the first gas station, and sure enough, the truck had 22-24 psi all around, under-inflated even when empty. We pumped those babies up to the maximum on the tire sidewalls (around 45 psi, as I recall), and drove the rest of the way home straight as an arrow, even at 70 on the Interstate.
