Ok yes, I know there's tons of info about this but I'm evidently not processing it properly (I'm old ). My 97 psd is only romping/loping when I start in neutral, not in park. That means its not the range sensor (I think). What would it be then?
Thanks, Vinny

 

Actually, it probably is the range sensor, only it's the Neutral position that's failing rather than the Park position. The sensor/switch works like the HVAC fan speed, a "stepped" series of resistors; as you move the shifter, the resistance across the two terminals to the sensor goes up and down (one resistor in series at a time). It could be that for some reason, in Neutral, it's not sending the right resistance value to the PCM. Or it could just be out of adjustment in some way that it works in Park and the driving gears, but not in Neutral. Might be interesting to start it in Neutral, and while it's romping, gently move the shifter toward Reverse and toward Drive, see if at some point the romp goes away. Just a WAG.

 

Thanks for the info, makes sense to me. I'll try that and see what happens. BTW- I can easily change the range sensor...... but out of adjustment? How do I remedy this ?