Q: Check Engine Light is on - codes P0313, P0299, P0304

asked by on

Around 90k miles had CEL with codes p0313,p0304 car ran poorly and had shop look at it and replaced a coil pack and spark plugs. Around 110k miles CEL returned with p0304 error code returned replaced the other 3 coil packs and new spark plugs. Around 130k miles CEL returned again with error codes p0304 and p0299, I did nothing and reset my CEL. Another 600 miles and CEL returned with error code p0304 I took to shop and they replaced 4 injectors and performed a carbon cleaning. Less than 100 miles CEL returns I do nothing except reset CEL. CEL returns with error code p0313,p0304, and p0299. Where do I start? Do replace the downstream sensor on throttle body? No unusual noises, occasional rough start when cold, not very noticeable

Hi there. Based on what you’ve described, this could be a combination of faults between 2 or more things; however, I don’t believe the coils and spark plugs are at fault. One of the codes is set during a low fuel misfire (lean condition), one is specifying a misfire on cylinder 4, and one is a turbo related code; all based on a generic code investigation.

The make and model of the vehicle helps, but is not necessary at the moment. When a low fuel pressure misfire is set, there is a lean condition that has been detected by the sensors and one of the codes is telling us in which cylinder this is occurring. A possibility is a restricted fuel injector, loose injector harness, poor pin fit in the wire harness, and an air leak near that cylinder’s port in the intake manifold.

I’m leaning more towards a leak or crack somewhere creating an air leak since we also have a turbo related code stored and an intermittent rough start when cold. I strongly suggest having a qualified technician perform an inspection to determine the root cause. YourMechanic has several available technicians that can assist you with a Check Engine Light inspection and determine exactly what is giving rise to codes P0313, P0299, and P0304.

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. Check Engine Light is on - codes P0313, P0299, P0304

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: Misfire P0304 and shaking

This may be related to fuel injectors not receiving the correct current or a faulty or dirty idle air control valve. As you know, the fuel injectors receive a certain electrical pulse that allows them to spray the correct amount...

Q: Q: EPC light on

Hi there. The EPC light will come on when there is a malfunction with your engine being sensed. Your vehicle will automatically limit the amount of throttle usage to help prevent further damage to your engine. This feature is designed...

Q: Q: Getting error code P0304

P0304 means the engine computer has detected a severe misfire on cylinder 4. This could be due to a bad ignition coil, spark plug, fuel injector, or valve train issue. If the issue is not resolved, further damage to the...

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...
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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...