Another P0308 Misfire Post

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Mar 10, 2018 | 06:55 PM

#21

SiracHaile

Thread Starter

Overlanding

Joined: Feb 2013

Posts: 21

Likes: 2

From: Los Angeles, CA

Update:
Replaced wires with Magnecor 8mm wires. Replaced spark plugs to Bosch Platinum+4 plugs. Replaced coil packs with new Bosch oem. Replaced fuel injectors with reconditioned replacements. And..... still cylinder 8 misfire.
At this point I’m thinking it’s something not related to anything with ignition or fuel or compression but possibly electrical or worse the engine.
I’m so lost now I’m clueless. And again this is only at startup. Anything else I need to check?

Mar 10, 2018 | 10:33 PM

#22

Saturnine

Pro Wrench

Joined: Jan 2018

Posts: 1,721

Likes: 258

From: Denver

How were the O-rings on the new injectors? Injector wiring look ok?

Mar 10, 2018 | 10:59 PM

#23

SiracHaile

Thread Starter

Overlanding

Joined: Feb 2013

Posts: 21

Likes: 2

From: Los Angeles, CA

All looked brand new. Injector harness looked fine no cracks or broken insulation. After looking into it more and doing more research cars that have this issue have head gasket leaks. So even though it’s all rebuilt, I’m going to pressure test the cooling system. This is becoming a nightmare....

Mar 21, 2018 | 03:47 PM

#24

stxscott

Mudding

Joined: Jan 2014

Posts: 108

Likes: 22

Please keep us updated on what you fine - I've got the intermittent 308 as well, but I haven't changed coil packs yet.

Mar 21, 2018 | 03:52 PM

#25

Dave03S

TReK

Joined: Nov 2011

Posts: 2,748

Likes: 506

From: Seattle, Wa

You can look into cyl 8 with a cheap ebay boroscope attached to your smartphone. That would at least rule in or out any HG issues there.

Mar 22, 2018 | 12:14 PM

#26

SiracHaile

Thread Starter

Overlanding

Joined: Feb 2013

Posts: 21

Likes: 2

From: Los Angeles, CA

Sorry for the lack of updates. I have done an internal check with a borascope while pressurizing the coolant system with 1.25 bar of pressure. I didn’t find any leaks in the cylinder. This was done at operating temperature. I also discovered if I hold the throttle at 2000rpm during startup SAI the misfire doesn’t happen. I did that for a week until all my monitors were completed to pass smog. Next morning didn’t do that and the SES light came on. So it may also be a vacuum leak on the cylinder maybe the gasket isn’t fully seated. I need to do leak down to see if the valves are fully seating or try a vacuum leak test.