Rx300 Gas Knock

[bowtie3]

My wife's 2000 RX300 [54,000 miles ] has had a periodic gas knock for the past year or so. We've always used 89 octane fuel in it and generally get it from BP/Amoco or Shell. I've had it in to the dealer several times in the past year for this problem and always leave dissatisfied. They continue to tell me it's the fuel we're using. I've even used 93 octane several times and had the same results. It used to happen right after a fill-up, but lately it will do it at even a half-tank. Everything is normal and then taking off from a traffic light and BINGO, there is the gas-knock again. When it happens I pull the ECU-B fuse for few minutes and that solves the problem til the next time. I put a bottle of Chevron Pro-Guard in it about every 3 months. Does anyone have any ideas about this problem? Thanks.

[tburk]

My wife's 2000 RX300 [54,000 miles ] has had a periodic gas knock for the past year or so.  We've always used 89 octane fuel in it and generally get it from BP/Amoco or Shell.  I've had it in to the dealer several times in the past year for this problem and always leave dissatisfied.  They continue to tell me it's the fuel we're using.  I've even used 93 octane several times and had the same results.  It used to happen right after a fill-up, but lately it will do it at even a half-tank.  Everything is normal and then taking off from a traffic light and BINGO, there is the gas-knock again.  When it happens I pull the ECU-B fuse for few minutes and that solves the problem til the next time.  I put a bottle of Chevron Pro-Guard in it about every 3 months.  Does anyone have any ideas about this problem?  Thanks.

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Bowtie,

while trying to diagnose a problem i was having with the fuel delivery system i came upon this little gem of a post. Turns out this might be the best modification i have ever performed on any of my cars. i will be looking into the possibility of performing the same procedure on my other car this weekend.

http://www.lexusownersclub.co.uk/knowledge..._v2&id=152&c=11

in our Rx 300 I too had knocking and pinging during start up of the vehicle, when it was somewhat cold, and usually for the first 15 minutes of driving, then on the highway it kinda disappeared. my problems all started with a check engine light with a dtc code of 01707, i think, which is lean in bank one. something like that. ok, so after i performed the procedure, using carb cleaner spray [dont use brake cleaner] and one Qtip to remove the solid buildup from the sensor wire shown in the diy, the check engine light has not returned. an unexpected result was that the pinging has gone away.

my recommendation is that you try this procedure and see how it treats you. its easy and free. it took me about 20 minutes from start to finish.

good luck!!