1990 ford ranger, 2.9 runs up to temp then starts running rough and stalls. restarts like its hot. changed water pump and fan clutch
We had similar issue with a 2003 Ford Ranger. It turned out to be the cam shaft synchronizer. Apparently a common problem with Rangers. There is a sensor that will go bad and cause the problem that you describe. Might mention that to whoever you take it for service. The local Ford dealer charged about 400.00 for the sensor and the actual synchronizer.
Search Ford Ranger Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford Ranger Experts