I was getting a CEL with misfire on cylinder three. I moved around the coil packs and the issue stuck with cylinder three. Next step was to replace the spark plugs which I did today.

Can you guys look at these and tell me what you think? They're from a 2000 S2k with 54k miles. I bought the car used about a year ago and I do not know if they have ever been replaced. By looking at the electrode wear I'd guess they are the original plugs from the factory.

The electrodes look a little whiter than I was expecting and the ceramic is turning brown from heat at the base. Does this look normal for high mileage plugs, or could it be leaning out? The car did have an Injen CAI when I bought it. I have since changed it back to stock with a new OEM filter. Maybe it was getting a lot more air through the CAI? I don't want to speculate too much. I'd rather get some educated opinions here.

 

I don't know if this helps but I had dirt between the coil pack and spark plugs on my S that was causing the spark to blow out under heavy load, all bad. No CEL though

 

verify your car had the plugs replaced under the plug recall they had.... run ur vin thru ownerslink or a dealer...
but im 100% CERTAIN ITS YOUR PLUGS!

 

Is the recall still in effect? I'll gladly swap these out for a spare set at the dealer if they'll let me.

 

if it has not yet been changed by the recall then yes you can....
if they have just swap them out...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S@nt0s &raquo;</TD></TR><TR><TD CLASS="quote">verify your car had the plugs replaced under the plug recall they had.... run ur vin thru ownerslink or a dealer...
but im 100% CERTAIN ITS YOUR PLUGS!</TD></TR></TABLE>

The have the S at the end of plug # so they are the updated ones

 

if you go to the dealer the plugs are like 70.00 go to shucks or napa.

 

Just to let everyone know...
Dealer wanted $17 per plug. Refused to price match with NAPA.
NAPA wanted $13 and it would take several days to get them.
My local Advance Auto had them for $9.99 and could get them for me the next day at noon. That's cheaper than I found them anywhere online.

This was for the OEM NGK PFR7G-11S. Part number: 7772.

 

ahhhhh i have a new set of denso's here they were $50

 

try to change to coil pack from the cylinder missfiring with another coil pack on another cylinder

take a look on your engine grounds too

 

Your IAC should regulate the amount of air coming in your engine via a CAI, that should not effect idle and the O2 sensor should regulate fuel delivery above idle since your CAI will allow more intake, I do not believe the CAI was the cause of one cylinder misfire, You need to get a snap throttle test done on a shop oscilloscope to see how all the cylinders are fireing and of course the technician needs to know how to read secondary spark patterns for a lean condition, it only takes a few seconds. This could be a lean fuel, dirty injector issue, there are plenty of items to look at for troubleshooting, your tune up of course is the first step but it is not the root cause of your problems.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S@nt0s &raquo;</TD></TR><TR><TD CLASS="quote">verify your car had the plugs replaced under the plug recall they had.... run ur vin thru ownerslink or a dealer...
but im 100% CERTAIN ITS YOUR PLUGS!</TD></TR></TABLE>
that's a very good point. but i thought that recall was for 2001's only. the dealership that ran mine's told me that the recall should have automatically went into effect on the next service and would have been replaced.
the recall was because of loosely torqued spark plugs.
i dont think a cai would lean out your car to that extent

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">try to change to coil pack from the cylinder missfiring with another coil pack on another cylinder</TD></TR></TABLE>

Did that first. That's why I thought it would be the plugs. From the looks of those plugs they were due for changing anyway.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I do not believe the CAI was the cause of one cylinder misfire</TD></TR></TABLE>

Never thought the CAI would cause the misfire. I was just wondering if it could contribute to excessive plug wear. The CAI was removed over a year ago anyway, so no worries.


I really thought those plugs would fix it when I saw how bad they looked, but the CEL came back on. The car is idling rough, but otherwise seems fine. It isn't a DD, so I'm not really putting mileage on it until the issue is fixed.

I'm going to pull the code again to see if it has changed. Originally it was P303 iirc which was a misfire on cylinder three. I'm probably going to try adjusting the valves next since I have no idea when/if it might have been done by the previous owner.

I just don't have time to mess with it very much right now which sucks because the weather is awesome.

Any other suggestions?