Rough idle when in drive

1983 OLDSMOBILE 98
120,000 MILES • 5.0L • V8 • 2WD • AUTOMATIC
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OLDSREGENCY
  • MEMBER
  • 1 POST
Smooths out immediately upon acceleration. Smooth idle in park. I’ve changed plugs, wires, PCV, distributor cap and rotor, coil pack. Compression check all cylinders. Inspected for vacuum leaks. EGR Valve replaced. Have not replaced distributor yet. Not rebuilt carburetor yet. I’m at a loss why it shutters only sitting still in drive and not when in park. Thanks for your help.
Jan 3, 2021 at 9:42 PM
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STRAILER
  • ✓Experienced Mechanic
  • 55,511 POSTS
it sounds like it is lean at idle under load. I would do both the carburetor and distributor also can we pull a spark plug to check the color? These guides will help us fix it:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-to-change-spark-plugs

Please run down these guides and report back.
Jan 6, 2021 at 1:14 AM
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