Go Back   Tahoe Forum - Chevy Tahoe Forum > 2000 - 2006 Chevrolet Tahoe / GMC Yukon / Cadillac Escalade Year Models > Technical Discussions

Welcome to the Tahoe Forum - Chevy Tahoe Forum.
Register to remove these ads.


Technical Discussions This forum is for technical discussions related to customizing your Tahoe/Yukon



Reply
 
Thread Tools Display Modes
Old 10-28-2008, 09:55 PM   #1
Mongo
Tahoeforum Noob
 
Join Date: May 2008
Location: Montgomery, AL
Posts: 3
Mongo is on a distinguished road
Can spark plug gap affect mpgs?


Register to remove these ads. It's free!
I have a 2003 Suburban and just changed out the AC Delco spark plugs. I gapped the new Autolite platiunum plugs to .60 as stated in the owners manual and repair manual. However, the plugs I pulled out were gapped at about .50 to .53, the 2004 spec. Now, I've lost about 3-4 mpgs on my driving. Does the spark plug gap affect the fuel efficiency that much? Should I pull the plugs and gap them to the 2004 spec? I also changed out the AC Delco fuel filter with a WIC fuel filter. If anything, I expected the mpgs to improve NOT worsen. Any thoughts on this anybody? Thanks!

Last edited by Mongo; 10-28-2008 at 10:08 PM.
Mongo is offline   Reply With Quote
Old 10-29-2008, 12:32 PM   #2
73shark
Full Access Member
 
73shark's Avatar
 
Join Date: Apr 2007
Location: KC, MO area
Posts: 1,390
73shark is on a distinguished road
Default

Probably should have stuck w/ AC Delco plugs gapped at the recommended gap. For whatever reason, current electronic ignition systems are sensitive to plug brand.

Put some Bosch platinum plugs in a Dodge minivan once and mileage and power fell off. Replaced w/ some new Champions which it came with and everything was fine. And the platinum electrode on the Bosch was completely burned away down to the insulator after about 1K miles.
73shark is offline   Reply With Quote
Old 10-29-2008, 06:53 PM   #3
Mongo
Tahoeforum Noob
 
Join Date: May 2008
Location: Montgomery, AL
Posts: 3
Mongo is on a distinguished road
Default

Interesting...thanks! The AC Delco plugs weren't gapped to the recommend gap though. They were gapped to about .50-.53 whereas the recommended gap is .60. Will I make things worse if I pull the plugs and regap them to .53?

Quote:
Originally Posted by 73shark View Post
Probably should have stuck w/ AC Delco plugs gapped at the recommended gap. For whatever reason, current electronic ignition systems are sensitive to plug brand.

Put some Bosch platinum plugs in a Dodge minivan once and mileage and power fell off. Replaced w/ some new Champions which it came with and everything was fine. And the platinum electrode on the Bosch was completely burned away down to the insulator after about 1K miles.
Mongo is offline   Reply With Quote
Old 10-29-2008, 06:59 PM   #4
JennaBear
Supporting Vendor
 
JennaBear's Avatar
 
Join Date: Feb 2008
Location: CA
Posts: 587
JennaBear is on a distinguished road
Default

I would suggest gapping to .04 inches. GM revised their specs to .04 since the original .06.
__________________
http://www.blackbearperformance.com/images/Signatures/JennaBear_L.gif
Some Show and Some Go

Performance Tuning and Parts Dealer
JennaBear is offline   Reply With Quote
Old 10-30-2008, 02:36 PM   #5
Mongo
Tahoeforum Noob
 
Join Date: May 2008
Location: Montgomery, AL
Posts: 3
Mongo is on a distinguished road
Default

Thanks, JennaBear! I'll that a try and see how she responds. Appreciate it!
Mongo is offline   Reply With Quote
Old 10-30-2008, 03:16 PM   #6
JennaBear
Supporting Vendor
 
JennaBear's Avatar
 
Join Date: Feb 2008
Location: CA
Posts: 587
JennaBear is on a distinguished road
Default

You will be surprised the difference that a gap change can make!
__________________
http://www.blackbearperformance.com/images/Signatures/JennaBear_L.gif
Some Show and Some Go

Performance Tuning and Parts Dealer
JennaBear is offline   Reply With Quote
Old 11-04-2008, 02:00 AM   #7
Black Dog
Full Access Member
 
Black Dog's Avatar
 
Join Date: Feb 2008
Posts: 828
Black Dog is on a distinguished road
Default

It can absolutely affect mpg, and performance, efficiency. It can only be gapped correctly or it gets worse from there. Too little gap is like muting it and too much is like misfiring. If you're not adjusting it in consideration of the ignition system, combustion chamber, fuel induction and things like that then you should probably just go with the plugs recommendation.
Black Dog is offline   Reply With Quote
Old 01-26-2009, 04:04 AM   #8
MRGREG5000
Tahoeforum Noob
 
Join Date: Nov 2008
Posts: 6
MRGREG5000 is on a distinguished road
Default

I only use ngk plugs in my hoe.....ngk makes ac delco plugs and ac delco robs you compared to the ngk equivelent......use ngk tr55 gapped to .40
MRGREG5000 is offline   Reply With Quote
Old 01-28-2009, 12:55 AM   #9
KarenCaren
Tahoeforum Apprentice Member
 
Join Date: Aug 2008
Posts: 20
KarenCaren is on a distinguished road
Default

Wow. that gap changes a lot in mpg. Thanks for giving me the info about the gap. When I change mine I will definitely go for 0.40 gap.



______________
mercedes parts
KarenCaren is offline   Reply With Quote
Old 01-29-2009, 02:11 AM   #10
MRGREG5000
Tahoeforum Noob
 
Join Date: Nov 2008
Posts: 6
MRGREG5000 is on a distinguished road
grin Spark plug type and gap


Register to remove these ads. It's free!
For years the debate has been to use ac delco or not to use ac delco........first and foremost ac delco is made and manufactured by ngk.......why buy ac delco when the same plug ngk makes is 1/3 of the price.......ac delco is almost 50.00 a set of 8 for my 99 tahoe.....ngk same plug .....19 dollars and change.......dont be fooled buy people who say only use ac delco......do some research and youll see the truth.....and some tahoes came with ngk from the factory depending where they were assembled......now chevy used to state ....gap the plug at .60.......it even says that under my hood on a sticker.....but now chevy changed it to .40,,,,,,,the .60 gap makes a tahoe idle ruff.....the idea is that the bigger the gap you can go with a smmoth idle than the better performance youll get......but less mpg.....the closest more mpg less power.......you can gap the ngk to .50 if your tahoe runs smoothly......i gap mine to .40,,,,,,,ngk plugs are pregapped to .40 and you just make sure they are.....now ..........the ngk plug you want is .....ngk tr5.....or ngk tr55........the tr55 is a hotter plug.....better mpg with tr5....i have tr5 gapped at .40,,,,,,good power and mpg......good luck and dony pay 50.00 for 8 spark plugs because they say ac delco..........OH YEAH .....DONT EVER USE BOSCH....CHAMPION....IF YOU WANT TO BE DIFFICULT YO CAN USE AUTOLIGHT IF YOUR IN A JAM, BUT NGK....NGK...NGK...NGK...NGK...

Last edited by MRGREG5000; 01-29-2009 at 02:12 AM. Reason: MORE INFO
MRGREG5000 is offline   Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



 
Advertisement

Other Sponsors






All times are GMT -4. The time now is 01:52 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
All rights reserved and copyrighted
Fully Driven Auto Network
GM Truck Forum
Ford Raptor Forum
Dodge Ram Forum
Chevy Cobalt Forum
Chevy Camaro Forum
FJ Cruiser Forum
Ford Truck Forum
88-98 GM Truck Forum
73-87 Gm Truck Forum
Ford Expedition Forum
Chevy Equinox Forum
Chevy Cruze Forum
Jeep Liberty Forum
Jeep Forum
Dodge Ram SRT10 Forum
Chrysler 200 Forum
Scion xD Forum
Scion xB Forum
Dodge Challenger Forum
SRT Forum
Nissan Titan Forum
Buick Enclave Forum
Cadillac Forum
Cadillac XTS Forum
TRD Forum
Central US Mopars
Southeast Mopars
Cadillac CTS Forum
Oklahoma Dodge Ram Club
Softball Forum