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)
80,000 ths
.060"
On a 1990 Buick Electra Park Avenue, the spark plug wires connect to the ignition coil pack and the spark plugs themselves. The ignition coil pack is typically located on the engine, and each wire should be routed to its corresponding spark plug in the order specified by the firing sequence. Ensure that the wires are connected securely and routed away from any hot surfaces or moving parts to avoid damage. Always consult the vehicle’s manual for the correct firing order and specific wire routing.
The firing order for the 1990 Buick Reatta, which is equipped with a 3.8L V6 engine, is 1-6-5-4-3-2. The spark plugs are typically arranged in a way that aligns with this firing sequence to ensure proper engine performance. It's essential to follow this order when replacing spark plugs or performing ignition system maintenance to avoid engine misfires.
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.