I have a 95 Silverado with 239 000km on it. Replaced ignition coil, cap & rotor, plugs & wires, fuel filter and catalytic converter. It has started giving me troubles, as it will chug violently when moving at any speed if the rpm's are at 1500-1750. It will feel like a complete loss of power for half a second, then surge forward again under power. If I floor the go-fast pedal, no issues. It happens when I am rolling along at speed most times, after the overdrive kicks in and the rpm's drop down to the nasty range.

Head scratcher. I have not done any check for vacuum leaks, or tranny work in the last 3 years.

Any advice is appreciated.