Misfires fixed!

After many hours of head-banging I finally solved the misfire issues! I had previously compiled a list of possible issue that I used as a checklist for eliminating possible faults one by one. 

Now, lets review the list of suspects from an earlier post:

  • Bad coilpacks
  • Bad gas (water etc.)
  • Bad spark plugs
  • Bad MAF
  • Vacuum leak
  • Low fuel pressure
  • Bad crank position sensor
  • Bad O2 sensor
  • And several others.

From just about every post and article I read on the internet, coils and plugs were on, or near, the top of the list of usual suspects. I had previously upgraded coils and plugs when I tuned the engine to stage one back in november 2016, so I figured they were OK. I did fix a few vacuum leaks thinking it was it, but the problem was still there.

I then went on and replaced the following items:

  • Spark plugs
  • MAF
  • Crank position sensor
  • O2 sensor
  • Fuel filter
  • MAP sensor
  • PCV valve
  • PCV check valve (pancake valve)
  • Misc. check valves

As it is a 15-year old engine, most of these parts needed replacement anyway, so I figured this was a golden opportunity to get it done. Unfortunately it did not resolve the misfire issues and I was running out of ideas.

As a stroke of luck, I got a hold of four coils from my brothers 2001 VW Passat before he sent it to the scrappers. I threw them in there to see if it made any difference – and voilĂ  – the engine purred like a kitten!

Lots of work, lots of parts changed and the issue was what everyone said it would be… Lesson learned, listen to the majority and change the obvious culprit first.