TBI slow to return to idle

[Dually Sublazer]

Awesome! I havnt changed my O2 sensor yet cause i have a dual exhaust to install and will move the bung then. Brian is who i got my chip from. He's tons of help and told me about the heated sensor. Im curious about my converter now...... Last couple times i drove it, I noticed if in gear and stopped idle is smooth. If i let it roll (inches) with brake applied to hold it back, the engine surges. Like a couple hundred RPM's, up and down. Stops when yhe truck does or if i take off...... New converter may be in order.
Posted via Mobile Device
Posted via Mobile Device