[Val Walkinshaw]

Originally Posted by ember1205

Just thinking here...

You mentioned that you were observing misfires... Lack of ignition could increase fuel present in the exhaust which could then "trickle down" to everything else you're seeing. If you haven't already, and since you have the pieces on hand, maybe this is a good time to swap the plugs and then swap the wires.

Misfires could be caused by a variety of things and some of the things on that list could be connectivity issues that could trace to the wires or even the plugs themselves and spark not getting through 100% of the time.

Yes at various times I have experienced a stumble, it's stalled and typically when the RPMs are ranging around 600 while idling it's a little bit rough. Shortly after that I routinely was doing misfire diags and on a few occasions cylinders six seven and eight had misfires anywhere from 10 to 30 but no more than that. This last diag I only got one. Intuition tells me my problem is going to be related to the plugs. There's a lot of signs and symptoms that point to other issues that are all very good possibilities but there's just something in my gut that tells me I'm going to find something probably in cylinder 8 which is the worst one to access because it's up against the firewall.... I took a look at the purge valve tonight and they don't make that easy to get at. You have to take the intake manifold cover off and I was struggling with that. I'm only mentioning that because I was doing some exploration and mentally collecting data about what I'm noticing. Sometimes we don't always know what we're looking for but we sure as hell know when we find something that isn't right and I guess that's what my intuition was trying to help me find.

At this point my game plan is to put in the new mass air flow sensor tomorrow and then run some diagnostics. If I'm still symptomatic my next plan of attack is plugs and wires. After that.... Maybe taking a look at fuel rail pressures and inspecting the injectors. I'm going to roll the dice because I really don't think it's O2 sensors so I may dig deeper into the purge valve. I don't believe in throwing parts at a car but my personal opinion is that my parts Canon maxes out at $250. If I've gotten to that point and my issue has not resolved it's time to resort to a professional. The good thing is that the car runs and it's winter. It's not my daily and as of late she's become more of something I enjoy on the weekends and less of a track Queen.

Thank you for your input and I don't think you're way off base. My intuition hears you loud and clear.

[bishopts]

I would say do plugs and wires before anything. Leave the MAF alone. If you still have rich trims change the oil. Its a cheap dice roll that will rule out contamination. I know you said you sent your oil out to get tested but those techs can be just as half ass as dealership techs. You could have got results back from a completely different car. So change your oil, don't add any additives in it and look at the trims at operating temperature. You will move your data from assumption to assurance.

[Val Walkinshaw]

Update.

Installed the MAF sensor.
SO far so good.


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