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Gonna try a different plug/coil pack combo.... NGK Ruthenium HK
We've already heard all the "Stick to AC Delco" arguments, so don't bother.
I know a lot of people just openly dismiss manufacturers claims, and sometimes they are right to do so, but not always.... Case in point, Pulstar spark plugs.... https://youtu.be/-jkfbgT3_OI?si=Cn9xUVRSg3w4xTVw https://www.youtube.com/watch?v=ZrQM-PRT4ds DOWN-Side, and it was huge, after just 6,000 miles, the bike would start loosing power over 60MPH, put the old factory plugs back in & problem vanished. Now they were the Pulstar Platinum plugs like Project Farm used, and perhaps the lower melting point vs Iridium might have been a factor, as the 600 does run at about 4,000RPM at 60MPH. Several video's are available of various vehicles running Pulstar's with improved Dyno measured HP & Torque in motors ranging from 150HP to 400HP. Bottom line, great for the drag strip where you're regularly rebuilding your engine & want the absolute most HP you can get... but not for every day driving IMO. I will not try Pulstar's in the HHR due to various intermittent problems reported with them & HHR's, as well as the short life span I experienced with the Platinum's, potentially leading to very high cost per mile.... I WILL however be putting in these newish plugs from NGK - Ruthenium HX plugs, as well as NGK U5180 coil packs in about a month. Why Ruthenium? Ruthenium has:
Here's a guy who has been running these for years & giving regular updates, this is his third update after 63,930 miles. Though I don't know why he would change gap so much vs spec, that seemed to have burned out the ground electrode by his 4th update on 2 of the cylinders... But he apparently likes then cause he replaced them with Ruthenium plugs again. BTW... How on Earth is Rock Auto (thank you, bless you, thank you) so much cheaper than anyone else.... $9.26 / plug vs $18 / plug locally or $13.30 / plug from carid - $34 / coil vs $69 / coil locally or $42 / coil from carid |
RA has volume of sales!
AC Delco plugs last me approximately 100,000 miles, no drop in performance or fuel mileage. ive changed plugs for people who just bought their HHR or Cobalt and have over 170,000 miles on OEM plugs The gaps were still pretty tight into .040. I could check those as they were to be discarded. Let us know how your experiences are with your experiment. |
You might consider Amazon; 41-103 for under $8. Evidently there is now an IP (improved performance) version.
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Just ordered the new plugs & coil packs, should arrive just in time for start of vacation on Monday!
Finally got a chance to check out the current plugs in the LS. They appear to be the original factory plugs with Denso coil packs - my local Chevy dealer also replaced the factory packs on the LT with Denso when I took it in for the 100,000 mile service. All 4 plugs on the LS have this dark ring around the bottom of the ceramic: https://cimg1.ibsrv.net/gimg/www.che...eb646173b8.jpg I was also able to determine that the Chevy dealer did not check the plugs / coil packs when I took the LS in for diagnosis: https://cimg7.ibsrv.net/gimg/www.che...026cd67177.jpg You can clearly see on Cylinder #2 coil bolt where I pulled it off to check the plug, while the other 3 cylinders have no tool recent tool marks. You can see an OLD tool mark on cylinder 1 bolt but nothing at all on cylinder 3 or 4. Here are the plugs, all of them appeared to have some liquid on the threads, doesn't smell like oil or gas though, but maybe it's the fuel system cleaner I put in last tank fill-up - RedLine Si-1. https://cimg3.ibsrv.net/gimg/www.che...07ae38981d.jpg Kind of hard to see, but 2 & 4 have slightly rounded over edges on one side of the center electrode. #4 & #3 were both at 0.042, #1 was at 0.043, and #2 was at 0.038, I re gapped them to 0.040 before putting them back in of course! And just to reinforce the notion that the Chevy dealer didn't bother to check the coil packs / plugs, here you can clearly see the tool marks from me removing & reinstalling them: https://cimg9.ibsrv.net/gimg/www.che...41a99368bc.jpg |
The dark ring is normal, it is really difficult to gas seal between steel and porcelain.
I would be concerned about the wetness on the anodes on 1 2 4. #2 is the only one out of spec (.040-.043). |
A fun test, for different plugs. Please keep us informed.
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Originally Posted by donbrew
(Post 959821)
The dark ring is normal, it is really difficult to gas seal between steel and porcelain.
I would be concerned about the wetness on the anodes on 1 2 4. #2 is the only one out of spec (.040-.043). 2008 and earlier 0.037 to 0.043 2009 and later 0.040 All 4 were wet on the threads, doesn't really smell like gas or oil??? All 4 had a dark, almost black dry spot on one side of the ground strap / anode. I'm guessing that it's carbon buildup from the exhaust side. |
Haynes manuals can give wrong information. My 2007 2.2 L61 recommended gap was .040 the same gap they 41-103 plugs come set at
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101549 is current mileage, bought it with 100729 miles, came with 2/3 tank of gas, put a tank & a half in it so far. I reset the gas mileage readout when I left the dealer, it's currently showing 25.5mpg, which seams about right.
Would be nice to run at least 3 full tanks of gas for a more accurate MPG, but not going to wait that long. Gonna swap out the coils & plugs in the morning! I honestly don't expect to see much improvement, probably not even enough to definitively say "it's the plugs". Hopefully it'll clear out the occasional miss-fire's I've been seeing: seven on cyl 2, three on cyl 3, and twelve on cyl 4 in 9 trips over the last 400ish miles, but I've only been recording the longer trips over 20 miles one way. |
For better fuel mileage, I suggest a new air filter, clean the throttle body and MAF sensor. After you finish addressing the misfires. Also take the valve cover off and inspect the timing chain, the front guide is known to fail as are the fasteners.
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