Misfire on Cylinder 2,4 and 6 - Help!!!!!
 

Hello all.

So i have a strange issue - My 986 Boxster S - tiptonic is showing misfire on cylinders 2 4 and 6!
I have bought a new set of coils and new set of plugs for all 6 but still the same issue - what could be causing this issue on both banks!

Another fault it has come up with is P0413 0 Secondary air control valve A open circuit is that to do with the MAF and could that be the issue?

Thanks in advance!

Always helps to know the year of the car...........

I knew there was something missing - its 2004

it's best to list all the codes. Are you using a generic reader or durametric? Are they pending or set?

These faults codes were brought up on the MAC Tools - Mentor Touch Pro Diagnostic Scan Tool

P0413 - Secondary air control valve A open circuit
P0300 - Random / Multiple Cylinders Misfire Detected
P0302 - Cylinder 2 Misfire Detected
P0304 - Cylinder 4 Misfire Detected
P0306 - Cylinder 6 Misfire Detected

Thats all on screen

Hi Byrnsey. I don't want to send you down a rabbit hole, but have you taken a look at your fuel trims? Is the car running rough? If the problem with the SAI is causing a lean condition at idle (RKAT will be some value positive above 0) I'm pretty sure that can cause misfires especially at low RPMs. Here's a link from ScannerDanner that made me respond. As a symptom, he mentions that "customer has replaced plugs and coils in an attempt to fix". He is focusing on a leaking intake manifold gasket, but lean at idle is lean at idle (I think!).

https://www.scannerdanner.com/chapter-1-misfire-id-compression-test-vacuum-leaks-fuel-trim-head-gasket-restricted-exhaust-low-power-dvom/86-misfire-caused-by-a-vacuum-leak.html

If the car is running rough and you find that your fuel trims are indicating lean at idle, perhaps pull some of the vacuum hoses in the area of the SAI and test them with a vacuum hand pump to ensure they hold vacuum? There's also an electronic change-over valve in the SAI that you may be able to activate within Durametric to aid in diagnosing. Here's a link to keep you on track if you start to pull and test those vacuum lines:

http://986forum.com/forums/boxster-general-discussions/64576-vacuum-line-clarification.html#:~:text=The%20manual%20says%20y ou%20should,inches%20of%20vacuum%20at%20idle.

Best of luck!

Hi Byrnsey2, I just experienced misfires on Cyl's 2,3 & 6 last night all at the same time. The car has been running better than ever!

Did you end up figuring out why your's was doing this???