1989 Caprice 305 180,000 miles. Yes it is old and tired but it runs.

Anyway, the car starts and idles fine. Then when you put it into drive, it stutters and stumbles. Put it back into neutral or Park and it idles nice. Drive it 5 miles and the LEAN code comes up.

I'm thinking it does not recognize the car is in drive and the ecm is not adjusting the fuel delivery for the extra load of drive.

There should be a park/nuetral safety switch AND a park nuetral switch. My guess is it's the park/neutral switch which is tied into the ecm. I've checked varous manuals and can't get a definitive answer on if this switch exists and if so, where it is located. I only find vague references to it "on some models..."

The wiring diagram from a haynes manual shows a Trans position switch which is probably on the steering column and it shows 2 wires going to the automatic transmission. For me, reading a wire gram is like reading sanskrit..

Any comments on my diagnostics (guess!) or the nature of those 2 trans references in the Haynes manual would be appreciated.