I have a 5 speed that runs great until you try to run around 30mph. on 1995 GMC 1500 Pickup

when you run around town doing 30mph the truck jerks really bad. You can give it gas and it stops, but if you try and run lower constant speed it will give you whip lash. replaced coolant senor, plugs and wires, rotor cap and button, fuel filter and seaform. what to do?

Asked by for the 1995 GMC 1500 Pickup
It's about time for the distributor to give some trouble, this is a common problem. Remove cap and check for side to side movement of the shaft. Suggest replacement of the assembly with a 'new' unit! Can find a shop with a scope to test the ignition system if needed, that will tell the tale! Even some of the older oscilloscopes will work on this system! Can not beat a scope for pinpoint testing!!!