Toyota Repair: Need very high idle to keep engine running & idles very rough, toyota tercel, independent shop

Question
Would appreciate you help on the following problem.   1985 Toyota Tercel automatic with connected air-conditioning but not working. Mileage shows 53,000 but I believe the engine was rebuilt.
Problem started after going over a small local mountain. After got back to level ground the engine stopped everytime I stopped. To keep it going I would have to rev it up at the start and keep the idle high to keep the engine alive.  Since that time I have changed the oil filter, put in new spark plugs, and tightened the carburetor bolts.  Latest thing I've noticed is that when I first start it up, the engine idles smoothly (at high idle because I had to increase the idle to keep the engine runing once it got rough) until I gas it and it starts to warm up in a minute or less.  Then the engine begins to idle roughly until it starts to go into a cycle where the engine goes from high idle to almost stopping and back to high idle and so on. If I lower the idle too much the engine stops after starting it.  No problem with starting it. The cycling from high revs to almost stoping seems to occur even when the car is in Drive.  At same time the engine cycles fron high to low revs can see the choke or similar pulling the link to the carb value back and forth.
Note: On Thursday I called my local Toyota dealer and was told they could not see me until April 12th. In any case, if I know what to do, I would perefer to fix it myself if it's practical.


Answer
Could be a carburetor problem, these are complicated and are partially computer controlled and expensive to replace, I have no clear cut anwser for you, I have no idea why the dealer can not take you in until april, doesn't sound normal, try finding another dealer or a good independent shop to diagnose the problem.