2004 Jetta codes

I have a 2004 Jetta. Recently it through a code saying it had a misfire. Then it shows up that it was multiple cylinder misfire and the cat was performing below normal. I stopped at a store on my way home from getting the codes read and when I started my car the check engine light was flashing and the car acts like it’s going to die. It would hardly accelerate and shakes and has a hard time shifting. It’s like it has no power the the RPMs rev high before it shifts. I made it home but don’t want to drive it. Any ideas what it is? The spark plugs are new. I saw that it could be the cat is bad, a vacuum issue, or fuel pump or filter.

You should not drive the car with a flashing check engine light.

In order for us to even make a guess as to your Jetta’s problem, we would at least need the error codes given to you by the parts store. The numbers, not the description. P0123, ect. It would also be helpful to know what engine you have and how many miles on it.

A flashing Check Engine light indicates a major misfire is occurring.

If you continue to drive the vehicle while this is occurring, you run the risk of damaging the engine and the catalytic converter(s).

What Does a Flashing Check Engine Light Mean?

While a solid check engine light means you need to bring your vehicle in at your earliest convenience, a flashing check engine light means it is urgent. If you see your check engine light flashing, do not drive your car! This flashing icon means that there is potential damage to your catalytic converter, which is not cheap to repair. Driving your vehicle with the check engine light flashing can cause further damage.

You should have your car towed to the shop if this light is flashing as long as you are in a safe location. If you are somewhere that you would not be safe waiting for a tow truck, drive to a safe location and then deal with the issue. Your safety is always more important than your car.

Tester

Get the misfires fixed and the cat codes should clear themselves.

I know not to drive it but I was a few blocks from home so I got it home. The codes were P0300 p0301 p0302 and p0420

Random cylinder misfires, misfires on cylinders 1 & 2., catalyst efficiency below threshold.

Tester

Could be a weak spark. If it has one coil and no coil packs a failing coil would cause it to happen to more than one cylinder at once. Usually the cylinders farthest from the source are the worst. With a weak spark it gets worse at high throttle and / or low RPM.

With no power maybe it is a fuel pressure issue? Sometimes a filter can clog suddenly if you run very low on fuel and the debris at the bottom of the tank get sucked up. If it’s a vacuum leak it usually gets better when you’re at full throttle, since there is no longer much vacuum in the system.

New spark plugs and this happens? Hmm, did you replace them yourself? How long ago? What did the old plugs look like? Oily? Are you sure the new plugs were the correct type for the engine? …you never told us what engine you had or how many miles on it… Did the coils snap firmly onto the new plugs?

I’d start by removing the plugs and inspecting the both ends. The electrical connection for arc or burn marks and the engine side for oil fouling or electrode damage.

Post back with what you find.

I would check the coils. On our Passat of roughly that same year they were known to fail frequently.

This era VWs were known to have failed coils. It sounds like you have exactly what is described here:
VW Ignition Coils Failing? It’s Stall the Rage. (vwproblems.com)

I’d replace them (4 separate if it’s a turbo, one with 4 combined if it’s not), they’re about $100 total from Rock Auto. I’d also do the plugs (unless they’ve been replaced lately).

I might get accused of ‘throwing parts at it’, but it’s just such a common problem, I’d take that risk.

So I replaced the coils and that seemed to fix everything. But then while driving the light came on with code p0420. Any ideas?

I hope your catalytic converter didn’t get damaged by all the misfiring.

Here’s one list of possibilities. Start with the cheapest ones first. Before replacing the cat, have a mechanic check the O2 sensor function.

  • Faulty Three-way Catalyst Converter Bank 1
  • Exhaust Tube
  • Intake Air Leaks
  • Faulty Oxygen (O2) Sensor
  • Faulty Fuel injector(s)
  • Leaking Fuel Injector (s)
  • Faulty Spark plugs
  • Improper Ignition Timing
  • Faulty Engine Control Module (ECM)
  • Dirty Air Filter

So I had to replace the coil pack and the spark plugs have been done. It drove normal at first but I noticed that when I was in park it would still chug a little and didn’t seems to have as much acceleration. Well the P0301 code came back (cylinder 1 misfire) and I am at a lose.