My wife has a 2001 Buick Regal and after 80,000 miles we have had nothing but problems. The car acts like it is starving for gas so I took it to the shop and they replaced the fuel filter then it ran okay for a few days then went right back to square one.
So far the fuel filter has been replaced three times so I really doubt that this is the problem. You can be driving at 45 mph take your foot of the accelerator and the engine will die. Trying to restart it is a chore and when you do turn it over you smell a carbon like smell in the cab.
Do you think it is oxygen sensor, fuel pump going out or PCV valve that needs replaced? Also the catalytic converter has been replaced and injectors taken off and cleaned.
You need to step it up and put a new fuel pump in your Buick before you burn your engine up. The carbon smell that you are smelling means your car is running lean which basically means that your Buick is not getting enough fuel.
Please let me know if the new fuel pump resolves these issues.
I hope that this helps and thanks for writing in.