synikal1022 Posted April 23, 2009 Share Posted April 23, 2009 Hello guys and gals.....im new to this site and it looks GREAT!!!....My issue is that my 1998 ls400 with 120k on the clock runs great with premium and with mid-grade gasolines; the issue is that with premium fuel my check engine light comes on and the techs adviced me that its a catalytic converter inefficiency......when i run mid-grade gasoline it still runs great and even gets better mileage. What gives since the car requires premium.....thanks in advance for the info. <_< Quote Link to comment Share on other sites More sharing options...
Lucky13 Posted April 23, 2009 Share Posted April 23, 2009 Oh my Gooooooood Quote Link to comment Share on other sites More sharing options...
Marklouis Posted April 23, 2009 Share Posted April 23, 2009 Oh my Gooooooood no doubt lucky13... all i can suggest synical is to use the search option in the top right header, there are plenty of topics on this subject...beware of overexposure! Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted April 23, 2009 Share Posted April 23, 2009 I think we're all so tired of talking (arguing :D) about gas. haha Welcome to the club though!!! One thing that will help you tremendously IS in fact the search button up there :) I, however, don't believe your CEL would be attributed to the octane rating of the gasoline you fill your car with. What are the codes? Have you had them read? Quote Link to comment Share on other sites More sharing options...
eatingupblacktop Posted April 23, 2009 Share Posted April 23, 2009 Welcome to the club! Don't take offence, but we really don't need another thread on grades of fuel. There are too many around already! Check exactly what dtc comes up. Cat probs have nothing to do with grade of fuel. Quote Link to comment Share on other sites More sharing options...
lasik124 Posted April 24, 2009 Share Posted April 24, 2009 hahah oh my goodness haha (i laugh at the shell comerical every time though with the so called " higher Octane to give you more power bullsh**) but welcome Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted April 24, 2009 Share Posted April 24, 2009 Well don't you know? It's nitrogen enriched. and makes your car go, VVVVVVVVRRRRRRRROOOOOOOOOOMMMMMMMMMMMM!!!!!!!!!!!!!!! :D Quote Link to comment Share on other sites More sharing options...
nc211 Posted April 24, 2009 Share Posted April 24, 2009 Actually, I've been on this board for a long time, and I don't think I've ever seen a problem where the required gas would trip the cel, but the lower grade would not and produce better results. I'm interested in what the codes might be? I assume you've got the gas cap on tightly though, as that will trip the cel sometimes. Don't mind these guys. I'm willing to bet that if I looked hard enough, they've probably asked questions that warrant their responses too. You get "freebies" for the first 20-30 posts before us old guys start asking if your shoe laces are too tight. Quote Link to comment Share on other sites More sharing options...
eatingupblacktop Posted April 25, 2009 Share Posted April 25, 2009 Don't mind these guys. I'm willing to bet that if I looked hard enough, they've probably asked questions that warrant their responses too. You get "freebies" for the first 20-30 posts before us old guys start asking if your shoe laces are too tight. Gotta give NC props for reminding us that, although it might be "sameold sameold" for some of us, for others, it's a brand new problem, often with a brand new Lexus and a brand new forum. Good to have someone put things in perspective from time to time. Quote Link to comment Share on other sites More sharing options...
dcfish Posted April 25, 2009 Share Posted April 25, 2009 Don't mind these guys. I'm willing to bet that if I looked hard enough, they've probably asked questions that warrant their responses too. You get "freebies" for the first 20-30 posts before us old guys start asking if your shoe laces are too tight. Gotta give NC props for reminding us that, although it might be "sameold sameold" for some of us, for others, it's a brand new problem, often with a brand new Lexus and a brand new forum. Good to have someone put things in perspective from time to time. Cheers to that Old blood breeds new blood, This is one of the foundations of these forums B) God Bless. Quote Link to comment Share on other sites More sharing options...
synikal1022 Posted April 25, 2009 Author Share Posted April 25, 2009 Thanx for all the info guys and gals. One of my buddies that works at a toyota dealership advised me that in our area premium can be very high in ethanol and that it could be messing with the oxygen sensor and causing the CEL to come on. Wish i could know without spending big bucks at the dealership :( ....other than that my car is perfect!!!!! even with 122k on it. Best vehicle i have ever owned. Quote Link to comment Share on other sites More sharing options...
jcrome04 Posted April 25, 2009 Share Posted April 25, 2009 only 10% ethanol tops right? I don't think it would trip a CEL. It COULD just be as simple as a bad O2 sensor...... Quote Link to comment Share on other sites More sharing options...
PureDrifter Posted April 25, 2009 Share Posted April 25, 2009 only 10% ethanol tops right?I don't think it would trip a CEL. It COULD just be as simple as a bad O2 sensor...... worse than a bad O2 sensor is one that is taking its sweet time to die, the readings are out of spec enough to trigger a CEL for a catalytic inefficiency issue, but not out of spec enough to trigger the O2 sensor failure. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.