Faulty plug wires or bad coil or coil wire.
Check firing order
Disconnect the battery, remove the boot cover and spark plug cables, and pull out the old spark plugs. Put in the new spark plugs, replace the boot cover, and spark plug cables, and reconnect the battery.
Power brakes use engine vacuum to get their power. If the engine is out of tune, the loss of vacuum will cause it to run rough. Try changing the spark plugs.
have u checked spark plug wires, ignition coils, timing,spark plugs or had it hooked to a reader?
the spark plugs are located on the front of the engine under the hood
Remove the spark plugs wire and remove the plugs wit a spaerk plug wrench or socket.
One at a time
Check spark plugs and wires
It passably the Alternator, or the spark plugs. No way to really tell, but that's the common reasons why.
how to replace spark plugs wires 1992 buick century v 6 3300 stationwagon
Follow the plug wires down to the plugs. The front three are easy I recommend trying to start on the three in the back first and working downhill! Good luck can be tricky.
It could be the spark plug wires that's what was wrong with mine.