Hello I just bought a 1994 ford ranger 2.3L single cab. What maintenance should I do asap. I did the basic stuff, new coolant, checked the oil, new battery, even replaced the radiator. What else should I look into doing?

 

Reverse the hoses on heater core at the firewall to reverse the circulation thru the core, this will help the core last longer, you should do this on any vehicle when you change coolant or every few years

1994 2.3l is a SOHC Lima engine
First used in a 1974 Pinto last used in 2001 Ranger as a 2.5l SOHC, so also called "The Pinto engine", and Lima because it was made in Ford's Lima, Ohio engine plant
In 1989 these got dual spark plugs and an ICM(ignition control module), 1989-1994 with the older EEC-IV computers

Both spark plugs fire at the same time this adds a bit more power, there is no alternating, lol
With engine running you can unplug either coil pack's 3 wire connector, to disable spark plugs on one side, if engine starts to miss then 1 or more spark plugs on the working side are bad, repeat by disabling other sides coil pack
You should do this once a year, because there is no other way to tell if one spark plug has failed, the loss of power is not that much
And you can drive it with one coil pack unplugged, ran fine on 4 spark plugs from 1974 thru 1988, just less power

Its a good reliable engine, but built like a tank, its heavy
It uses a timing BELT so that needs to be changed every 80-90k miles, but its a non-interference engine so if belt slips or breaks no engine damage will occur

Rangers got a 2.3l DOHC Duratec engine in mid-2001, totally different engine, so googling 2.3l Ranger will get mixed results, lol, and the 2019-2024 Rangers also use a 2.3l engine, turbo charged