Skip the auto shop - Our mechanics make house calls

Q: Misfire in cylinder 2 and 6

asked by on

When I first cold start it every morning it runs perfectly no problems. A good 20 minutes pass and it starts misfiring and the whole car shakes. It shakes at a point where the steering wheel shakes also. I also hear a tapping sound when I first start it up but goes away and very faint after a 5 minute drive. If it helps I get 13.8mpg now.. a week ago I got 17mpg. Is it the spark plugs or something more major?

My car has 294500 miles.
My car has an automatic transmission.

It is possible that you have an ignition coil going bad. Once heat builds up, resistance in the ignition coils increase. If you have a weak coil, it will sometimes cause a misfire when it is hot.

The misfires are why your fuel milage is worse. With two cylinders not making power, it may take more fuel to produce the required power. The tapping sound may be caused by incorrect valve adjustment or other valve train related components. A certified technician, like one from YourMechanic, will be able to diagnose the cause of the misfiring issue and assist you with repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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: My Jeep Wrangler will crank but not turn over.

Hi there, thanks for writing in. I'd be happy to help. I recommend also checking the camshaft position sensor, as this also can impact the timing/spark issue. As to the fuel pump, I would recommend checking the fuse for this...

Q: Check engine light

Did the cam shaft or cam shaft sensor get replaced. You are having misfires and should get the vehicle scanned to see if one of the codes is to a misfiring cylinder. You may have leaking oil from the valve...

Q: transmission not catching gears and over revs

Hello and thank you for your question. It seems that the 3rd and 4th clutches inside the transmission are slipping. This is the reason why you are hearing a ticking noise under the transmission and it seems to not shift...

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...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...