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?

Need advice from certified mechanic? Get help now!

Over 1,000 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
  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: Two mechanics have not been able to repair misfire.

Hi there. Check the intake for a possible vacuum leak around the cylinder 4. If there is no vacuum leak around the cylinder number 4, then there could be a burned valve. Check the compression on all of the cylinders...

Q: 1999 VW Jetta Poor acceleration

The check engine light tells you that the Engine Controller (ECU) has detected a fault and stored a trouble code. So the best place to begin is to have the codes read and interpreted bu a technician. It's possible you...

Q: I just had a diagnostic performed on my car and the following error code came up P0299 boost control sensor.

Hi there. Check to see what the oil pressure is in the engine. If the oil pressure is low, then the P0299 code can appear. Also, check for the EGR operation and see if its sticking. A faulty EGR will...

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...
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...