Motor missing at high rpm

[DWilson]

Hi I've posted this before about my motor missing between 6000 and 7000 rpm and many people have said it's a bad coil over plug, is this the correct part to attempt to fix the problem?

03 04 05 06 NISSAN 350Z Ignition Coil 22448AL61C / 5

Thanks.

http://cgi.ebay.com/ebaymotors...ories

[evildky]

that is a cop and it says it's for a 350z so I guess it's right

you said you miss was at 6-7k pm? what is redline in these cars? possible the "miss" is you hitting the fuel or spark cut from the rev limiter?

[DWilson]

Thanks for responding, the rev limiter is 7000rpm so it shouldn't be missing at 6000rpm, I think it's a bad cop, I can give it a try anyways.

[evildky]

which cylinders cop do you think that missing? you gonna rotate it cylinder to ylinder? also you checked the plugs? gapped them?

[DWilson]

Hey thanks for responding, plugs are fine, what will rotating the COPs do? I don't know which cylinder is missing, if I buy a new COP and try it in each spot I might be able to figure it out, my father says the car should be running rough at all rpms not just at high rpm, he thinks it's a fuel/air problem? What does gapping a plug do and how do you do it?

Thanks

[evildky]

I meant rotating cop's as in you are buying 1 but don't know which cylinder si the issue

gapping the spark plugs is setting the gap betweenthe electrode and the ground strap, if a gap is too wide it cna start to blow out at higher rev's

have you done any work tot he car recently? your car is an 06, no warranty left?

[C-Kwik]

Hey thanks for responding, plugs are fine, what will rotating the COPs do? I don't know which cylinder is missing, if I buy a new COP and try it in each spot I might be able to figure it out, my father says the car should be running rough at all rpms not just at high rpm, he thinks it's a fuel/air problem? What does gapping a plug do and how do you do it?

Rotating the COP will allow you to test and find the bad one through trial and error (assuming you actually have one bad COP). A bad coil, regardless of arrangement doesn't necessarily mean it will run poorly all the time. If there is some issue with being able to reach sufficient saturation then it would be most noticable at higher RPM's where there is more sparks per minute than at idle.

Gapping a plug is typically not done on modern cars anymore as plugs usually come pregapped (especially since the use of platinum and iridium in OE applications became standard as the buttons of precious metal can be dislodged while gapping). But, it would be a good idea rto check for excess wear on the plugs as a plug that has too large a gap between the electrodes will require a higher voltage to bridge the gap (especially under higher loads). Though, unless you drive a lot of miles per year, it would be unlikely that your plugs would be subject to excess wear as the OE platinum plugs should last for quite a while. Couldn't hurt to check though. Pulling the plugs could help you find other sources of problems by "reading the plug". Its one of the first things I do when there is any sort of miss, stumble or lack of power.

[DWilson]

Hey thanks for the info, appreciated, I'll look into that.

[HeavyDuty]

Isn't there a spec for checking the ohms of resistance on each coil?

If you do pull a plug, the "reading" involves the shape, surface texture and color of each plug. Do a google search on running lean or running rich.