1998 Cadillac SLS

Engine Performance problem
1998 Cadillac SLS V8 Front Wheel Drive Automatic 155000 miles

When I start my car it sometimes runs rough. Not all the time, though more often than not. When it's in park it seems to idle better. When at a stop sign in drive, it will be fine then sputter like a murmer then go back to normal, then sputter again. When driving on the freeway, it seems like it's not getting enough fuel but when I step on the gas it seems fine. When I put it in neutral, it runs like a champ!

Someone mentioned to me it could be clogged throttle body, or even plugs, wires. I changed the fuel filter thinking it might be the problem, but it wasn't. Any ideas? How do I run a code check?
February 6, 2009.

Sounds like a secondary miss due to arcing wires/cracked or worn plugs. If the wires still have cylinder #'s on them they are original. Check the coil terminals that the plug wires connect to, any sign of corrosion, replace the coil for that pair as well.

Feb 6, 2009.