Q: Rough idle/Check Engine light/Cylinder # 2 misfre

asked by on

Rough idle and check engine light came on. I had the code read (P0302 code - cylinder #2 misfire). I have replaced the #2 coil and driven it about 15 miles or so since - but still have the rough idle. Is there a chance this clears up as a result of the replacement? What are other likely causes - spark plug? Clogged fuel injection perhaps? Basically, I want to find out the most likely cause. Also, I want to check and make certain that I'm not risking some sort of extreme engine damage by driving over the next couple of weeks until I have the time to get it serviced.

My car has 235000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. The spark plugs may absolutely be the cause of your misfire. Even if only one cylinder is registering a misfire at this time, you should replace all of them at the same time. The spark plugs can be replaced every day and it would only improve your engine performance.They are the most likely component to cause these issues, as they are used so frequently and aggressively. Any part that works that hard is going to need extra attention. If you replace your spark plugs, and the issue continues, you can turn your attention to the fuel system. Additives can be mixed with the fuel to help clean the fuel injectors of any build up. Keep in mind the engine will burn the deposits that are broken free from the system and you may feel it when driving. It should be short lived and not cause any issues. Start by replacing your spark plugs, and take any further diagnosis from there.

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. Rough idle/Check Engine light/Cylinder # 2 misfre

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: Check engine light is on. Misfiring on Cylinders 3 and 4.

Before replacing all the coils and plugs you may need to have the engine decarbonized. The engine can have excessive carbon build up on the exhaust valves, cylinder head, and exhaust manifold. You should use engine combustion chamber cleaner on...

Q: Intermittent wiper speed setting is not working

The problem could be the intermittent wiper module in combination with the wiper switch or in the wiper motor itself. Problems occur with both of these components and only a component pinpoint test can narrow down the problem for you...

Q: Emergency brake stuck or rotors rusted

Hello. You are correct that the brakes might be rusted, not allowing the wheels to turn. It is also possible that if you used the parking brake, one of the parking brake cables might be too rusty, causing the cable...

Related articles

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...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...