Hi guys… I have a problem that’s driving me and the dealer crazy. I own a 2008 RX 350 that has been driving perfectly until six months ago. I was on the highway driving about 60mph when the car started to vibrate and reduce the speed by itself and resist any attempt I made to speed up!! I thought I had a flat tire so I pulled to the side of the road and surprisingly all tires were OK. And since then it started to do it from time to time… I took it to the dealer and they checked it several times and changed all parts that they suspected of being faulty and still did not resolve it. They checked the transmission, the ABS, fuel pump, just name it … and they could not find anything. Have anybody encountered similar problem? What was the solution? Please… help!

 

It sounds like something controlled by the computer, I guess the dealer would only change this if all else fails. I would lean towards a wheel speed sensor or something like that as it seems like the computer thinks your loosing traction and is de-throttling to regain control.
Jeff

 

Whoa, I haven't seen that kind of problem before. If you do find out, please let us know what happened?

 

This is a strange one. I would have guessed a fuel filter problem but did u say the dealer checked that out?
I have seen when a filter is clogged u can not get enoght fuel & that stops the vehicle from speeding up.

 

Thanks guys for passing by my thread. Jeff… all sensors were checked including the wheel speed sensor. Now the dealer is thinking about changing the computer itself!!! We are not sure if this will solve the problem. Xfirechief, the fuel pump and filter were checked too…

 

In a different vehicle, I had an intermittent fuel pump. The vehicle would at times loose power and die and 9/10 times would fire up right away. I was lucky in diagnosing the problem as I tapped the pump head and could hear it start pumping.

Your problem may not be due to the fuel pump but If you have any thing failing intermittently it would require a bit of luck to diagnose/fix.

Salim