I have a 1991 ford ranger xlt 4x4. Automatic transmission with a 2.9 liter. 106,000 original miles. New headgasket, fuel relay, fuel injectors, fuel and air filters, plug wires, ecm, o2 sensor, pcv valve, radiator, timing chain, water pump, fan clutch, fuel pump, thermostat and other components i cant think of at the moment...

What would cause this issue? It is intermittent, but irritates me lol

I appreciate any ideas

 

The idle air control (IAC) might cause that but usually affects the idle speed.

 

Thanks ! I just remembered, I replaced that too...