My 94 Custom with a 3.8 runs a little rough. It has 104kmiles. Over the past year it has had plugs, wires, alternator and a fuel filter. The car has run well until recently it stalled on my daughter going up a hill. She claims it shakes. Earlier in the month it went on a 600 mile trip with no problems. I ran it down the highway and got some smoke out of the exhaust like it was loaded up from alot of city driving. When I got home, I tried revving the engine only to have it cut out at 4000rpm. It would stay resume running when I would lift off the throttle but at 4000 it was almost like a kill switch.
Any ideas?

For city/suburban driving, should is 3 the preferred transmission selection to D? D seems to keep the revs way down.

Thanks,
Ray

If the car was in park the rev limiter kicked in causing the engine to cut out. This is a design feature that will prevent you from damaging your engine by over reving the engine while in park. If the engine refused to rev below that I would suggest a blocked cat but based on your description the rev limiter is the culprit.

As for the transmission setting D is designed to keep the revs down to improve mileage. This is the desired position unless you are pulling a long grade and the transmission is constantly shifting back and forth and then 3 might be a wiser choice. Also works on long downhill grades to prevent overuse of the brakes.