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Posted

Approaching 120,000 on 2000 GS 400. Running original spark plugs and have had no problems with misfires or poor acceleration. Highway mileage can sometimes approach 29 mpg. Question is whether I need to replace the plugs. The book says the iridium plugs should be replaced at 120,000 but it also seems to suggest that has to do with emissions issues and not performance. Any thoughts on not replacing the plugs now. thanks


Posted

Get either Denso long life Iridium's, part # SK20R11 OR NGK long life Iridium's, part # IFR6T-11. Those are both OE replacements & gap is .044"

:cheers:

Posted
Get either Denso long life Iridium's, part # SK20R11 OR NGK long life Iridium's, part # IFR6T-11. Those are both OE replacements & gap is .044"

:cheers:

thank you; very helpful info. ap

Posted

Iridium plugs are not OE. Your car came from the factory with either Denso or NGK Platinum electrode dual-ground plugs. Many of us (myself included) feel the Platinum plugs are best for cars that were "born" with them.

Posted

My 98 GS400 owners manual says car is fitted with iridium-tipped spark plugs & 'twin ground electrode' spark plugs for the GS300.

PF

Posted
Iridium plugs are not OE. Your car came from the factory with either Denso or NGK Platinum electrode dual-ground plugs. Many of us (myself included) feel the Platinum plugs are best for cars that were "born" with them.

The 2000 GS 400 was factory equipped with laser Iridium 'long life' spark plugs......not platinums. Check out the owners manual or www.ngksparkplugs.com or www.sparkplugs.com to varify. ;)

:cheers:

Posted

like i said also u can buy the OEM ones from sewell lexus for like 6-7 bucks each! check the link a few posts up[ i left before! i got them off thier ebay account for 6 bucks EACH! and these are oem plugs from a certified dealer!

brian

Posted
My 98 GS400 owners manual says car is fitted with iridium-tipped spark plugs & 'twin ground electrode' spark plugs for the GS300.

PF

My 1998 GS300 was originally equipped with platinums. Maybe my car is just not cool enough for iridium plugs? When given the choice I trust the car and the physical evidence over the manual every single time.

plugs.jpg

Posted
Approaching 120,000 on 2000 GS 400. Running original spark plugs and have had no problems with misfires or poor acceleration. Highway mileage can sometimes approach 29 mpg. Question is whether I need to replace the plugs. The book says the iridium plugs should be replaced at 120,000 but it also seems to suggest that has to do with emissions issues and not performance. Any thoughts on not replacing the plugs now. thanks

was this car even rated for 29mpg highway? i've never seen better than 22

brian

Posted

GS400 - Iridium

GS300 - Platinum

Use OEM replacements, Plain and simple ;)

Posted
Yeah - 29 with the engine off in neutral coasting downhill. Maybe. :lol:

Have gotten 28 or 29 mph on several trips of 220-250 miles while cruising at

70-72. Once filled up the tank and drove 60 miles on the NJ Turnpike and then refilled

and got 30 mpg all the while averaging about 68-70 mph. I don't drive hard and rarely use

a/c though open sun roof and driver window cancel out that saving. Just recently,

got 27 mpg on 350 mile trip averaging about 75 mph. Another reason I am reluctant

to replace the Iridium spark plugs which are claimed to last many times more than platinums.

All of the comments have been very useful and I thank all of you including the coasting

downhill guy who, at least, gave me a laugh. ap

Posted
Yeah - 29 with the engine off in neutral coasting downhill. Maybe. :lol:

.......recently, got 27 mpg on 350 mile trip averaging about 75 mph. Another reason I am reluctant

to replace the Iridium spark plugs which are claimed to last many times more than platinums.

All of the comments have been very useful and I thank all of you including the coasting

downhill guy who, at least, gave me a laugh. ap

You must have the GPriuS400! :D


Posted
Yeah - 29 with the engine off in neutral coasting downhill. Maybe. :lol:

You must have the GPriuS400! :D

HAHAHA GPriuS400.....i could put this on a straight drop and still not get 29 mpg!

um im a semi fat !Removed!.........jk im a big guy and i cant live without a/c! plus cracking window hurts mpg ALSO! i dont know anyone who has seen 29+ mpg but you! im getting 14-17 in the city depending on how i drive it and 20-23 on highway

brian

Posted
Yeah - 29 with the engine off in neutral coasting downhill. Maybe. :lol:

You must have the GPriuS400! :D

HAHAHA GPriuS400.....i could put this on a straight drop and still not get 29 mpg!

um im a semi fat !Removed!.........jk im a big guy and i cant live without a/c! plus cracking window hurts mpg ALSO! i dont know anyone w ho has seen 29+ mpg but you! im getting 14-17 in the city depending on how i drive it and 20-23 on highway

brian

Hey, I was pretty surprised with 28+ mileage on the road and even checked the odometer against the highway mileage markers to make sure of accuracy. Driving around the city in stop and go, I usually would get 19.8-20.4 but did not check all that often. Always have burned 93 octane and change the Mobil 1 every 3,000 miles which is probably ridiculous, but I keep cars a long time. Anyway, the car may be a freak but with mileage consistently like this, that is one of the main reasons that I may just skip changing the Iridium plugs. ap

Posted

Hey, I was pretty surprised with 28+ mileage on the road and even checked the odometer against the highway mileage markers to make sure of accuracy. Driving around the city in stop and go, I usually would get 19.8-20.4 but did not check all that often. Always have burned 93 octane and change the Mobil 1 every 3,000 miles which is probably ridiculous, but I keep cars a long time. Anyway, the car may be a freak but with mileage consistently like this, that is one of the main reasons that I may just skip changing the Iridium plugs. ap

just never seen or heard or that kinda mileage from the gs series! ITS NOT EVEN FACTORY RATED FOR THAT! so........ :unsure: who knows but it still doesnt sound right

brian

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