Shahed

that's interesting, i had new pads and discs all round about 2 weeks ago. I've got this rattling kinda knocking thump noise whenI go over bumps. At first I thought it may be a loose exaust fitting of some nature? However, I have now discoverd that the problem lies with the Rear Drive Shaft - basically a a shaft between wheel and centre shaft. The inward or ourtward joints when worn or loose accounts for this noise. unfortunately, an expensive operation at Lexus Dealer so try find someone who knows the car well to buy them online, and fit them much cheaper than dealer rates !

I have the same problem on my 2005 Rx300. As you describe, ionly when over something like 10mph, as it comes down a spped-hump, I feel a knocking sound/thump! Really annoying me. Probnelm is, I just noticed this after fitting LPG conversion with tank where spare wheel used to be underneath the car. Any ideas??? Just a quick question on the LPG conversion ! Did this affect your Lexus warranty ? I have extended warranty on my 2003 Mark 2 and my Lexus dealer said that if I fitted LPG, the warranty would become invalid. Although I have a Rx300 2005 car, my warranty has already expired due to current mileage of 67,000, and I did not opt for extended warranty, don't really believe in them as most warranties tend to have a cap of £1000.00 per claim! In terms fo the LPG conversion, I would sugest you do lots of research before you decide to convert. I found out that it was not simply an option of Yes or No, there are many different systems on the market and everyone you speak to will swear theirs is better than the others for x, y and z reasons??? All I can say is that I did lots of research and was convinced to go for the Prins System. However, after speaking to the installer, I took his recommendations to go for his bespoke system which has a Voltran ECU and Brand New Vogas Injectors on SGI. I a 60L tank beneath the car where the spare wheel used to be. Trust me, this cars drives like a Rocket on this system, infact you cannot tell the difference when it switches between the two fuels, and it seems it drives smoother and faster on LPG. I would definitely recommend it if you want to save pounds on your fuel bill!

I have the same problem on my 2005 Rx300. As you describe, ionly when over something like 10mph, as it comes down a spped-hump, I feel a knocking sound/thump! Really annoying me. Probnelm is, I just noticed this after fitting LPG conversion with tank where spare wheel used to be underneath the car. Any ideas???

I bought a 2005 Rx300. Recently had a LPG kit fitted, runs fine. However, I have started to notice a knocking noise from beneath my car, kinda coming from the back or centre. At forst I thought it might be the lpg tank (located beneath) or loose fittings in the boot however, after trying to locate the problem, I do not seem to be able to find the problem? Anyone have any ideas? Again, only noticeable when drvign over potholes or coming off speed-humps etc.