Q: One month ago cel came on I changed spark plugs to after market plugs. One month later cel on again with misfire code.

asked by on November 18, 2016

Cel keeps coming on. 1st dealer gets misfire codes on 3 and 4. Says could be after market plugs so changes them to. Subaru plugs. 150 miles down road cel on again. Next Subaru dealer another 650 miles road. Misfire code on 3 and 4. Couldn't find anything, drives fine, reset codes. 500 miles down road cel on again. Next Subaru dealer misfire code on 1, 3, and 4. Says valves need adjusting. Getting very frustrated with non definitive solutions which keep costing more money. I am out 360 for spark plug replacement which was obviously not needed since it did not fix the problem...

My car has 130000 miles.
My car has a manual transmission.

Check Engine Light is on Inspection $94.99 - $114.99 Get a Quote

If the spark plugs hadn’t been changed until 130k, it was time for the to be replaced anyway. This is probably why the dealer went with that repair as worn spark plugs can cause misfires. Ignition coils are another part that may fail and cause misfires when they malfunction. A compression test and cylinder leak-down test will show if there is a problem with the valves. You can try having the coils replaced and the valves adjusted by the dealer. Consider hiring an experienced technician like one from YourMechanic who can come out and conduct the same tests as the dealer could and determine the cause for your check engine light.

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

What kind of coolant should I use?
It’s imperative that your vehicle is equipped with the coolant, especially if you use the air conditioning. The ideal coolant mixture for your car is 50% water, and 50% ethylene glycol antifreeze.
How do I lock or unlock the doors inside the car?
Door locks provide important safety and security while you’re inside the car, as well as when you leave it. Being able to lock the doors ensures that no one can open it from the outside while you’re behind the wheel,...
Car sputters in First or Second gear
The wet weather was a good hint toward an ignition misfire. The water will make the spark plugs and wires too short to ground. You would most likely be able to hear a snapping noise from the plug wires in...
No air coming from vents
Try to put the blower on high speed and move the mode to floor or windshield to see if any air is felt or the noise from the motor is heard. If you hear the blower running but still get...
Knock sensor 2000 Chevrolet Lumina
Hi - first task is to recheck what codes are still present that represent a "knock sensor failure (https://www.yourmechanic.com/question/knock-sensor-1-by-dylan)". There may be an additional problem that has changed engine timing (worn timing chain for example) that is causing an engine...
Transmission making noise that relates to engine rpm.
Hi there. Shut the engine off and check the fluid on the transmission dipstick. If the transmission fluid is low and not registering on the dipstick, then top it off until it reads full. Then start the vehicle and top...
Is there grease in the left side front driver side wheel bearing
The wheel bearings on the front of your car are within unitized hub assemblies and thus the grease that is placed within when the hub is manufactured is permanently sealed inside. It will not leak out. If the bearing has...
locate fuse for windshield washer on 2002 toyota camry
The windshield wiper fuse is located in the fuse junction box under the left side of the dash. The fuse is a 25 amp fuse. It will be labeled wiper. Check the fuse to see if it is burned out....
I need a rack and pinion for my 2005 chevy silverado 1500, how much would that cost me
You can get a precise estimate by inputting your vehicle data into the "Get a Quote" panel at YourMechanic's power steering rack and pinion service page (https://www.yourmechanic.com/services/steering-rack-gearbox-replacement). Broadly, though, to give you an idea of the cost, if you do...

Related articles

P0103 OBD-II Trouble Code: Mass Airflow (MAF) Circuit High Air Flow and High Voltage Output
P0103 Trouble code definition Mass Airflow (MAF) Circuit High Air Flow and High Voltage Output The Code P0103 code is often associated...
P2763 OBD-II Trouble Code: Torque Converter Clutch Press Control Solenoid Control Circuit High
P2763 means a problem from the torque converter clutch pressure control caused by an electrical issue, transmission fluid problems or a bad solenoid.
P0559 OBD-II Trouble Code: Brake Booster Pressure Sensor Circuit Intermittent
P0559 means an issue with the brake booster pressure sensor circuit, caused by vacuum leaks and other issues within the brake booster system.