Step 1,,2,,3,, spark, compression, fuel,, if computer controlled ,,#4 scanning, those are the steps that apply to any basic trouble shooting procedure on any motor,,, computer controlled or not. You still need to start with the basics which ever the case. Occasionally a plugged converter will screw things up, head gasket could be the problem, plugged fuel pick up, after that it's pretty much a quick prayer for the 400K mile old beast, and a give her a humaine 45 between the sealed beams,,,,,!!!!!
Keep it simple with the basic steps and that's the ONLY right way to do it,,period. On electronic controlled cars there can be any combination of things wrong that will require a scanner, take it from someone who's been a machanic for >45 years. That's how it's done.