Skip the auto shop - Our mechanics make house calls

Q: Flashing Check Engine Light is on. The engine shakes at idle and has low power.

asked by on

My car started to shakes like a a piston isnt firing? How would I know,if is a dead cylinder or a bad coil I recently replaced sparkplugs and oiil I know it could be mechanical or electronics so I would like to know which order should I tske to diagnose the problem

My car has 170000 miles.
My car has an automatic transmission.

A: Hi, the first task is to extract the proble...

Hi, the first task is to extract the problem codes which are causing the Check Engine light to flash. Most auto parts stores will do this for free. I would suspect plug wires next, and check the condition of the distributor cap and rotor while checking the plug wires.

Pull one plug wire off at a time, then start the engine. If disconnecting the plug in one specific cylinder does NOT make a difference in how the engine runs, that plug wire is your first suspect. With the age of the car, and your mileage, replacing all of the wires is the right decision, even if only one wire is bad.

To avoid any unnecessary repairs, I would recommend having a misfiring inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: My radiator fan only turns on when my AC turns on.

Hello there, a couple of different items can cause the fan to not work like this. The most likely culprits are a thermostatic switch, fan resistor, temperature switch, low-speed or high-speed relay, or a wiring issue. If the vehicle overheats,...

Q: Huracan 5.0. creates white smoke on colder days

It probably is the valve seals. You want to hope it's not the head gasket blown. To check the head gasket is simple. I've got a video that tells you if your head gasket is blown. It's a simple test--the...

Q: I have oil and water mixing in the engin but there is no oil in on the plugs.

No. There is only 1 common possibility for this engine to get water into the oil, and that is a blown head gasket. This often, but not always, follows an overheating event, and some times also occurs with vehicle mileage...

Related articles

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...