Firing order is 1-6-5-4-3-2 Cylinders are numbered left to right 1-3-5 on the front of a FWD engine and 2-4-6 on the rear. On a RWD vehicle they are numbered 1-3-5 on the left bank and 2-4-6 on the right bank. https://www.youtube.com/watch?v=LmYYvMg_jCs
Check firing order
3.8 engine?? 1-6-5-4-3-2
For a 1990 Buick Century V6 3.3L engine, the manufacturer's recommended spark plug gap is .060" (1.52mm)
.060"
80,000 ths
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.
The spark plug gap for a 1993 Buick Century is: .045 for the 4 cyl 2.2 engine .060 for the V6 3.3 engine
1-6-5-4-3-2
Copy & paste this link into your browser and look carefully at the diagram. http://autorepair.about.com/library/firing_orders/bl-fo-8332.htm
Faulty plug wires or bad coil or coil wire.
the spark plugs are located on the front of the engine under the hood
Pull on it, its just stuck.