My 1993 5.2 Magnum automatic has developed an off idle stumble. Last year I had the intake off and replaced the plenum gasket, and did routine maintenance. Drove it for months since with no issues. Lately, it often stumbles and stalls when barely touching the gas pedal. Especially when warmed up, and parking, or going between Drive and Reverse. Doesn't happen when engine is cool. I have removed and cleaned the throttle body thoroughly. Tried swapping the sensors on the throttle body with used sensors from another running 5.2. Replaced the O2 sensor with a new one.
Replaced the PVC valve. Checked vacuum lines. No change. Still wants to stumble and quit. What am I missing?