Unpredictable behavior from a trusted old car can be disconcerting and possibly dangerous. Comfort derived from years of faithful service might become replaced by doubts in your Century's abilities. Thankfully, the components involved in such malfunctions are easy to get to, and inexpensive to replace. Engine options for the 1986 Buick Century include a throttle-body injected four-cylinder from the Pontiac Division of GM, a carbureted Chevrolet 2.8 liter V-6, and two versions of Buick's 3.8-liter V-6. When the 2.8-liter V-6 engine begins stalling, the first step in the repair is to troubleshoot the issue.
Cap and Rotor Tests
Remove the air cleaner to ease access to the distributor. Use a thin shaft screwdriver to release the distributor cap hold-down screws. Lift the cap clear of the distributor and set it aside. Remove the rotor from the distributor shaft by backing out the two retaining screws until they freewheel. Lift the rotor out of the mounting surface.2
Inspect the rotor surfaces for burned or pitted areas in the center of the plastic rotor body. Replace the rotor if any signs of arcing or decay are noted. Align the pegs on the rotor underside with the corresponding holes in the mounting surface to avoid installing the rotor backward. Tighten the attaching screws.3
Examine the inside of the distributor cap. Replace the cap if any cracks or black, fuzzy carbon tracks are evident. Inspect the coil contact brush, or button in the center of the cap. Replace the cap and brush if the button appears worn or burned. Install the air cleaner.
Disconnect the vacuum hose from the distributor advance and plug the hose with a golf tee or sharpened pencil.5
Drive the car until it reaches operating temperature or stalls.6
Replace the distributor pick-up coil if the stalling ceases while the vacuum advance hose is disconnected to remedy pickup coil supply wire fatigue. You will lose engine power and fuel economy by continuing to drive with the advance hose disconnected, even though the stalling condition is cured.