Among some other challenges I have with the tune for my vortec 383 TBI is an intermittent issue where it won’t register as an idle when speed is zero. Causes it to stay in closed loop even though I have the timer set at 12 seconds to go into open loop idle. Also causes a high idle of 750 or 800 even though commanded is 650. Also exacerbates my decel issues that is my other big tune problem.

Happened today on next start after a 30 mile drive. (Two hour delay after 30 mile drive and next start). I was lucky to have my laptop with me so I plugged it in and saw that idle status was not registering even though vehicle was not moving and PCM showed 0 mph vehicle speed. What would cause the idle status to not get set even though speed is zero? VSS? Loose connection somewhere? Ground? Note that shutting engine off and restarting resolves the issue - at least it has the few times this has happened in the past. I’d say it happens less than 1 in 10 times I start engine.