I recently bought an 85 4Runner. Drove it 6 hours home no issues. Slightly rough idle but nothing concerning. Then the next day on my lunch break it started running really rough and would not rev past 3000rpm. So I got it home and checked the TPS and AFM and both appear to be reading correctly on the voltmeter and I cleaned them and they seemed fine. I also did an oil change and spark plugs and nothing has helped. I’m super frustrated and running out of ideas any input that can put me in the right direction would be a huge help

 

I moved your post to a forum section that will get you more attention.

 

Plug wires, distributor cap/rotor, aux air valve, O2 sensor?

Just throwing possibilities out...
Pat☺

 

check for ecu error codes?

 

Do a block test for peace of mind. Most of the chain parts stores have them in their loaner program. This does an excellent job of testing for coolant and exhaust gas exchanging.(I.e. headgasket)
I feel like a broken record on this next question, but it’s important and insightful. Is the distributer adjustment lock bolt centered in the slot, or off to one side? And same with the TPS. Is it centered?

 

I’m in favor of collecting way more data before you throw parts at it. Maybe you can narrow it down to a cylinder- Pull spark plug wires one at a time while running to see if any cylinder is not contributing. Put a stethoscope on each injector to see if they are clicking. Put a vac gauge on it at idle and watch the behavior. Beyond that compression test and check valve clearances.

 

Could even be starving for fuel. I've gotten a bad batch of fuel on more than one vehicle that required a new fuel filter. You have to cover the basics with your troubleshooting. Approach it logically and take notes to keep it straight in your head. Plenty of help available on this forum. Good luck with it. You'll get it. Make sure to follow up. Dead end threads suck.