The spouse and I looked over the engine and played with filters enough to convince ourselves we didn't know what we were doing--but! The air filter at least looked fine and the small clear filter looked clear.
I gave the engine 10 minutes to warm up and took it to the freeway. After some getting used to it (really requires a lead foot compared to my Nissan), I had no trouble. Got to 95mph and maintained it easily. Lost my nerve to go any faster.
The mechanic looked it over for general defects and pronounced the engine in fine shape and that he thought it "just ran that way."
(Think they're called caster) bushings on front tires = $400
New steering wheel gear box = $700
Pricey, but not the astronomical costs I was warned of and not that different from the costs I was having on the Nissan month after month.
There's also rather horrifying rust holes puckered out from the wheel wells, like a small child with herculean strength had put his foot through each of them.
And they broke the bad news about the air conditioning using older model stuff. Has leaks too.
For the sluggish acceleration, he told me to throw Redline Diesel Catalyst in the next couple fillups. On my 4th fillup and just kept using the stuff--seems to get better and better.
Cost to get valves adjusted? $100. Something for the future.