1994 G20 automatic, vibration at idle in drive only

[adolphjohn]

My wife's 94 G20 vibrates badly when idling in drive. The vibration goes away in park, neutral and reverse. It also goes away at most speeds when driving. It has 64,000k, new NGK plugs, new wires. I changed them in hopes that would get rid of the vibration. New motor mounts (also changed for the same reason). Recently had a fuel injector replaced by the Infiniti dealer.They set the timing & idle and cleaned the throttle body. When not in drive it idles at about 850-900 as smooth as when new.

I have read of bad converter solenoids causing idle problems in other cars. Any experience with that here?

Thanks.John