I put bosch platinums in 2.2L sunfire. the originals had 93k on the plugs. the bosch platinums idled so rough, it triggered a check engine light. swapped them out for ac delcos. no check engine light. idle is normal. go figurequote:
Originally posted by john_ertw:
I have two vehicles with the 3.4L engine (Silhouette and Grand Am) and have heard the best plugs to use are either the AC Delcos or NGK Iridiums (part number TR55IX). I've heard problems with Bosch platinums (especially the +2 and +4, but also with the regular platinums).
I'll bet they had a supply problem with the Delphi AC Delco branded plugs and needed to get something quick, so they got a bunch of the equivalent NGK plugs. It's probably the same as the AC 41-921, especially when I look at the description on ngk.com. They certainly aren't cheap, though.quote:
Originally posted by Jason Troxell:
The factory platinums on our '01 GTP are just plain NGK, not even an AC-Delco name on them... (snip)
I think it is because they switched to Iridium plugs, and AC didn't make Iridium plugs. It was easier and cheaper to source them from NGK is my guess. I think the AC platinum plugs are very good plugs, at least for the GM engines that I have owned.quote:
I'll bet they had a supply problem with the Delphi AC Delco branded plugs and needed to get something quick, so they got a bunch of the equivalent NGK plugs. It's probably the same as the AC 41-921, especially when I look at the description on ngk.com
APP106quote:
Originally posted by Jim Spahr:
Vader, what would that lower temp Motorcraft pn be for a 94-96 LT1 5.7 engine? What is the cost compared to a double platinum AC?
Actually GM retained the rights to the brand name AC Delco.quote:
Originally posted by Matt_S:
To answer the original question, AC Delco is a brand name of Delphi Automotive, the parts company spun off of GM.