Q: replaced bad coil pack and new coil not sparking car starts but runs rough engine light on blinks sometimes

asked by on

Car started running rough while driving. tests revealed bad coil pack cyl 1&4. replaced coil still not firing now #6 not firing too. Car starts right up runs rough and even more rough when shift into drive or reverse engine light on and blinks when accellerator is pressed. Car has over 250000 miles but was rebuilt about 10 months ago. Car was operating fine and noticed gas milage began to decrease in last couple weeks this problem started 3days ago. Spark plugs and wires replaced about month ago. Would appreciate some direction to take troubleshooting or a diagnosis. Thank You.

My car has 250000 miles.
My car has an automatic transmission.

Hello and thank you for your questions. If your engine was rebuilt about 10 months ago, the question is to determine if the management system has been installed as well. With the symptoms that you are having, it sounds like the coil packs are old and in need of replace. You replaced numbers 1 and 4 and now number 6 is not firing. I recommend replacing number 6, 2, 3, and 5. This will ensure that you have all 6 coil packs that are new.

Just because the coil packs are okay during a test doesn’t mean that they are functioning correctly. Coil packs on Buick vehicles from 1998 - 2005 last between 150,000 to 200,000 miles. I also recommend having your fuel injection system flushed. Unless you have new injectors, the old injectors could cause a cylinder to fail, even though it is working correctly. These symptoms can cause the engine to have a rough idle and rough running during conditions. If you need assistance troubleshooting the rough running condition, I recommend having a professional, like one from YourMechanic, inspect the car and move forward with repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. replaced bad coil pack and new coil not sparking car starts but runs rough engine light on blinks sometimes

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Air filter clog stalling car

It may not have anything to do with the new filter you put in. The most likely cause of the problem of stalling after installing an air filter is that the inlet air tube has a crack in it or...

Q: Car is smoking, knocking and idling by itself.

Hello, thank you for writing in. The vehicle is overheating, and the other symptoms are related to it. If it has overheated passed a certain point, there may have been major damage done to the engine. At this point, the...

Q: Turbo 350 involved in flood

Hi There, I would suggest having the transmission flushed as there may be remnants of water that may have worked into the internals of the transmission, which will eventually cause problems with hydraulic pressure. I would suggest also having all...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...