It starts up readily. It runs a little rough at idle, as though a cylinder occasionally misses, for a minute. Idle speed starts at 600. I don't need to put my foot on the gas to keep it running. Over the next 10 minutes the idle speed slowly rises until it tops out at 1300. I've taken long drives (50 miles) and measured the idle at about that twice last week.
The idle adjust screw and fast idle adjust screws are all the way out. There's slack in the throttle cable at the carb end. The throttle and carb valves move freely.
I tried to find a vacuum leak both by putting my hands on every vacuum hose I could reach and spraying propane on them. I got no reaction.
I installed a new fuel pump 7 years ago. The plugs look okay. They're 15 years old but only driven 22K, the same for the distributor cap, rotor, plug wires, PCV, air filter, fuel filter; I replaced the oil and oil filter 9 years, 3K miles ago.
The idle has risen gradually from 800 12 years ago to 1170 in 2015 to 1300 this year. Spec is 700.
The Haynes mentions the dashpot, a device I've never dealt with. I'll fiddle with it next.
Unless I get a better idea, I'll replace all the vacuum hoses, plugs, etc - wave a dead chicken over it.
You-all have any ideas?
'87 toyota pickup dlx, 4-cylinder, 5-speed manual, 22R engine, red
One more thing: it doesn't have too much power when it's idling at 1300. If I lift my foot off the brake after a stop, it doesn't jackrabbit off. It'll move without giving it gas, but accelerates slowly. I would think that a car meant to idle at 700 would deliver a lot more power at 1300.