'97 GMC 5.7 Sierra Z71 needs OE Plugs

OssipeeSteve · 06-17-2008, 05:06 PM

I cheaped on the tune-up 40,000 miles ago not going with OE plugs and I think I'm paying the price in mileage. I used to get almost 20 mpg highway in the warmer weather (pre 10% corn in the gas, ethynol) and now its 16 mpg. Anybody got the word on the best plug for the truck with 137K miles?
Thanks, Steve

mudseeker · 06-18-2008, 08:41 AM

AC Delco..........

03chevy · 06-18-2008, 10:30 AM

i have had bad luck when not useing oem parts... i had a 87 z24 and used wells every three months i had to replace something. then i went to the dealer and got ac delco and no problems. so if you have a gm use only ac delco parts less headaches in the long run

OssipeeSteve · 06-18-2008, 10:50 AM

Thank you, Gentlemen. I'll post my highway MPG as soon as I have returned from my next trip with OE plugs.
Steve

jimbo543 · 06-19-2008, 04:01 AM

replace the t-stat, mileage will improve

z07 · 06-19-2008, 06:19 AM

I've got dyno numbers and 1/4 mile ET's that show no correlation between expensive plugs and performance. I do, however, run NGK Iridium plugs in our Corvettes simply because they are a pain to change and those last longer than others and they don't have the problem with the pucks falling off like the platinum plugs did. With all that said, I'd use the OE spec AC Delcos without hesitation in any application where they can be changed without too much effort.

ukrkoz · 06-20-2008, 07:48 PM

HALO plugs. OEM specific, only plug on the market proven by government and independent reseraches to improve power and mpg. don't expect miracles, acetone is for that, but it gives anywhere between 1.4 to 3.2% improvement. i have all cars i can on them and am very happy. no, i have no $$ interest in those.

leolkfrm · 06-21-2008, 11:57 AM

sounds like the o2 sensor might be getting weak. Check the voltage reading with a good scan tool and see if it may be in the lower end of range.

OssipeeSteve · 06-23-2008, 08:07 AM

Thanks, guys. Did pick up the OE Delco platinums. When I'm up my bud's place I'll put the scanner on for the O2.
Priciate it,
Steve

Diddly · 06-30-2008, 07:13 PM

Ustta do dyno tune-up in Inglewood, CA. My take on spark plugs is that the better Spark plug likely has more to do with matching the heat range with your driving habits. All city= hotter heat range all open road cooler plugs. Far as gas mileage your corn alcohol has less energy per gal= less miles per gallon. Supposed to drink corn licker not put it in your gas tank...........
Diddly

06-17-2008, 05:06 PM	#1 (permalink)
OssipeeSteve Full Member Join Date: Mar 2008 Posts: 16	'97 GMC 5.7 Sierra Z71 needs OE Plugs I cheaped on the tune-up 40,000 miles ago not going with OE plugs and I think I'm paying the price in mileage. I used to get almost 20 mpg highway in the warmer weather (pre 10% corn in the gas, ethynol) and now its 16 mpg. Anybody got the word on the best plug for the truck with 137K miles? Thanks, Steve

06-18-2008, 08:41 AM	#2 (permalink)
mudseeker Moderator Join Date: Feb 2006 Location: michigan Posts: 3,079	AC Delco.......... __________________ proud member of the 200k mile club http://s89.photobucket.com/albums/k2...eeker/smilies/ boys never stop playing with toys

06-18-2008, 10:30 AM	#3 (permalink)
03chevy Senior Member Join Date: Dec 2006 Location: jax,fl Posts: 799	i have had bad luck when not useing oem parts... i had a 87 z24 and used wells every three months i had to replace something. then i went to the dealer and got ac delco and no problems. so if you have a gm use only ac delco parts less headaches in the long run __________________ A dirty mind is a terrible thing to waste!

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06-18-2008, 10:50 AM	#4 (permalink)
OssipeeSteve Full Member Join Date: Mar 2008 Posts: 16	Thank you, Gentlemen. I'll post my highway MPG as soon as I have returned from my next trip with OE plugs. Steve

06-19-2008, 04:01 AM	#5 (permalink)
jimbo543 Senior Member Join Date: Sep 2007 Location: MN Posts: 161	replace the t-stat, mileage will improve

06-19-2008, 06:19 AM	#6 (permalink)
z07 Senior Member Join Date: Feb 2008 Posts: 149	I've got dyno numbers and 1/4 mile ET's that show no correlation between expensive plugs and performance. I do, however, run NGK Iridium plugs in our Corvettes simply because they are a pain to change and those last longer than others and they don't have the problem with the pucks falling off like the platinum plugs did. With all that said, I'd use the OE spec AC Delcos without hesitation in any application where they can be changed without too much effort.

06-20-2008, 07:48 PM	#7 (permalink)
ukrkoz Full Member Join Date: Feb 2008 Posts: 43	HALO plugs. OEM specific, only plug on the market proven by government and independent reseraches to improve power and mpg. don't expect miracles, acetone is for that, but it gives anywhere between 1.4 to 3.2% improvement. i have all cars i can on them and am very happy. no, i have no $$ interest in those.

06-21-2008, 11:57 AM	#8 (permalink)
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 432	sounds like the o2 sensor might be getting weak. Check the voltage reading with a good scan tool and see if it may be in the lower end of range.

06-23-2008, 08:07 AM	#9 (permalink)
OssipeeSteve Full Member Join Date: Mar 2008 Posts: 16	Thanks, guys. Did pick up the OE Delco platinums. When I'm up my bud's place I'll put the scanner on for the O2. Priciate it, Steve

06-30-2008, 07:13 PM	#10 (permalink)
Diddly Junior Member Join Date: Jun 2008 Location: Suthn half of Nortern Nevada Posts: 6	Ustta do dyno tune-up in Inglewood, CA. My take on spark plugs is that the better Spark plug likely has more to do with matching the heat range with your driving habits. All city= hotter heat range all open road cooler plugs. Far as gas mileage your corn alcohol has less energy per gal= less miles per gallon. Supposed to drink corn licker not put it in your gas tank........... Diddly