I have 1900 Ford Ranger 4 by 4. it only has 70,000. It starts but chugs until it is warm. here in Ak now it is never
They didn’t make the Ranger in 1900. Did you mean 1990? Does it have a carburetor or Fuel injection?
It should be injected. Try some Gumout Regane COMPLETE fuel system cleaner. CCDI can cause rough running if the engine only sees some short trip usage. It can flake off deposits that temporarily cause issues until the engine warms. It can also sound like piston slap in engines that aren’t known for the characteristic since the symptoms retreat in an identical manner. It’s fuel residuals that are left behind upon shut down.
This may not be the cause of your issue, but for the $6-10 and a tank of gas, it’s worth it.
No there was no ford in 1900. it is a 1990. injection