apatrules Posted July 19, 2008 Share Posted July 19, 2008 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 Quote Link to comment Share on other sites More sharing options...
sakataj Posted July 21, 2008 Share Posted July 21, 2008 replace them............can get them off ebay from sewells ebay page for like $6 a [;ug or off sewells page directly! http://www.sewellpartsonline.com/ brian Quote Link to comment Share on other sites More sharing options...
apatrules Posted July 22, 2008 Author Share Posted July 22, 2008 replace them............can get them off ebay from sewells ebay page for like $6 a [;ug or off sewells page directly! http://www.sewellpartsonline.com/ brian Thanks for the recommendation. ap Quote Link to comment Share on other sites More sharing options...
Lexusfreak Posted July 22, 2008 Share Posted July 22, 2008 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" Quote Link to comment Share on other sites More sharing options...
apatrules Posted July 22, 2008 Author Share Posted July 22, 2008 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" thank you; very helpful info. ap Quote Link to comment Share on other sites More sharing options...
2JayZ Posted July 24, 2008 Share Posted July 24, 2008 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. Quote Link to comment Share on other sites More sharing options...
pmf Posted July 24, 2008 Share Posted July 24, 2008 My 98 GS400 owners manual says car is fitted with iridium-tipped spark plugs & 'twin ground electrode' spark plugs for the GS300. PF Quote Link to comment Share on other sites More sharing options...
Lexusfreak Posted July 24, 2008 Share Posted July 24, 2008 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. ;) Quote Link to comment Share on other sites More sharing options...
sakataj Posted July 24, 2008 Share Posted July 24, 2008 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 Quote Link to comment Share on other sites More sharing options...
2JayZ Posted July 30, 2008 Share Posted July 30, 2008 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. Quote Link to comment Share on other sites More sharing options...
sakataj Posted July 30, 2008 Share Posted July 30, 2008 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 Quote Link to comment Share on other sites More sharing options...
2JayZ Posted July 31, 2008 Share Posted July 31, 2008 Yeah - 29 with the engine off in neutral coasting downhill. Maybe. Quote Link to comment Share on other sites More sharing options...
pmf Posted July 31, 2008 Share Posted July 31, 2008 May be the GS400 & GS300 does NOT share the same type of spark plugs? ;) http://sparkplugs.com/results_app.asp?prod...mp;AAIA=1316103 http://sparkplugs.com/results_app.asp?prod...mp;AAIA=1316113 PF Quote Link to comment Share on other sites More sharing options...
2JayZ Posted July 31, 2008 Share Posted July 31, 2008 May be the GS400 & GS300 does NOT share the same type of spark plugs? ;)http://sparkplugs.com/results_app.asp?prod...mp;AAIA=1316103 http://sparkplugs.com/results_app.asp?prod...mp;AAIA=1316113 PF I think he was saying the manual that came with his GS400 stated that the GS300 used iridium plugs. One owner's manual was printed to cover both the I6 & V8 GS. Quote Link to comment Share on other sites More sharing options...
dcfish Posted July 31, 2008 Share Posted July 31, 2008 GS400 - Iridium GS300 - Platinum Use OEM replacements, Plain and simple ;) Quote Link to comment Share on other sites More sharing options...
apatrules Posted August 1, 2008 Author Share Posted August 1, 2008 Yeah - 29 with the engine off in neutral coasting downhill. Maybe. 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 Quote Link to comment Share on other sites More sharing options...
2JayZ Posted August 2, 2008 Share Posted August 2, 2008 Yeah - 29 with the engine off in neutral coasting downhill. Maybe. .......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 Quote Link to comment Share on other sites More sharing options...
sakataj Posted August 4, 2008 Share Posted August 4, 2008 Yeah - 29 with the engine off in neutral coasting downhill. Maybe. 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 Quote Link to comment Share on other sites More sharing options...
apatrules Posted August 4, 2008 Author Share Posted August 4, 2008 Yeah - 29 with the engine off in neutral coasting downhill. Maybe. 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 Quote Link to comment Share on other sites More sharing options...
sakataj Posted August 6, 2008 Share Posted August 6, 2008 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........ who knows but it still doesnt sound right brian Quote Link to comment Share on other sites More sharing options...
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