: What are the best Spark Plugs



Rocc4Rocc
05-07-13, 11:47 PM
I want to change my spark plugs, and want to know what are the best ones on the market? I would like to boost my MPG if possible.

MoistCabbage
05-08-13, 12:27 AM
Use ONLY the correct AC Delco plugs, Northstars tend to foul most others.

You're not going to get any more MPG or performance out of a plug change.

Superjim
05-08-13, 09:22 AM
^^^^^^... What Moist Cabbage said...
Use AC Delco 41-987

RicktheRealtor
05-08-13, 10:45 AM
I've posted this before, but, again, I was very surprised that when I finally changed the plugs on my N*, the original, factory installed plugs were NKGs. (sorry, forget the number). I would suspect that in daily driving, one would be hard pressed to actually measure any mileage difference between brands. Those AC Delcos are probably made in China today, anyways.

Superjim
05-08-13, 11:02 AM
I've posted this before, but, again, I was very surprised that when I finally changed the plugs on my N*, the original, factory installed plugs were NKGs. (sorry, forget the number). I would suspect that in daily driving, one would be hard pressed to actually measure any mileage difference between brands. Those AC Delcos are probably made in China today, anyways.

Just bought a set of 41-987's the other day...
They are actually made in Japan... LOL
.
.
http://i76.photobucket.com/albums/j40/superjim1944/Mobile%20Uploads/20130508_100317_zps94d45892.jpg (http://s76.photobucket.com/user/superjim1944/media/Mobile%20Uploads/20130508_100317_zps94d45892.jpg.html)

RippyPartsDept
05-08-13, 12:03 PM
the acdelcos are most assuredly rebranded from another spark plug brand but who knows what they are exactly ... best to just stick with the delco's

they're not super expensive anyway

Submariner409
05-11-13, 08:48 AM
My money is on rebranded DENSO plugs - The original plugs in a lot of the late 90's - early 2000 Northstars were DENSO (My 2002 had them in it) the Cadillac Seville owner's manual uses a cross-referenced DENSO p/n (PT16EPR-C13), and the new AC Delco #41-987 is "Made in Japan", probably by DENSO.

Which car does the OP want to change plugs in ??? Does the 2007 Northstar still use #41-987 ?

If you believe the hype that cutesy spark plugs will give you increased gas mileage, I have a bridge to Brooklyn that I'll sell, cheap. If your existing spark plugs are over 100,000 miles old and are filthy and the electrodes are eaten away, then ANY new plug will give you some performance increase (you'll never notice it) - but by and large, the original double platinum AC Delco plugs are the best to use.

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I've posted this before, but, again, I was very surprised that when I finally changed the plugs on my N*, the original, factory installed plugs were NKGs. (sorry, forget the number). I would suspect that in daily driving, one would be hard pressed to actually measure any mileage difference between brands. Those AC Delcos are probably made in China today, anyways.

I seriously doubt the original plugs were NGK. DENSO, maybe. Today's AC Delco plugs (for the Northstar series, anyway) are boxed "Made in Japan".

RippyPartsDept
05-11-13, 09:41 AM
yes Sub, the 2006-2011 DTS uses 41-987 plugs (for both the 9 & Y engines)

Submariner409
05-11-13, 02:01 PM
Not too shabby - 12 model years of engine using the same plug - the things should be around for a while ...........

1BadCadSTS
05-11-13, 02:07 PM
The 07+ STS does too

The 05-06 calls for 41-986 no clue why they changed the gap. I swapped mine out for 987s and closed the gap to set them for the 986 gap.