95 Buick Regal misfiring

My Dad's 95 Regal has a problem. It idles great, but when the tranny is moved to D or R, it starts misfiring bad, the car jerks and shakes. Any ideas? Thanks in advance for your time.

Pretty general description, any check engine lite? Good wires and plugs?

Pretty general description, any check engine lite? Good wires and plugs?
Sorry, No check engine lights, plugs and wires have been replaced. Dad's mechanic told him the coil packs were ok. The engine does not backfire, just runs really rough. Again, this only happens when it is in gear. I had the same problem with a 97 Bonneville, except the problem was intermitent. Finally after replacing all three coil packs the problem disappeared. I am still suspicious of the coil packs, but I am not a trained mechanic. Thanks for your time.
John

Could be something is grounding out with a wire or sensor connector, recheck the plug wires for proper routing and connections.

Will check wires. Thanks for your time.
John

I'd be suspicious of the coil packs too. Get those checked. If they're bad that might be the answer to your problem. If you get the coil packs checked and they're ok, it would be time to check your fuel system. Is the fuel pump working Right? Are the fuel lines ok? When was the last time the fuel filter(s) was checked and/or replaced? Are the fuel injectors clogged? These are all questions you'll have to find the answer to if the coil packs aren't the problem. Keep posting, let us know how it goes, and good luck.