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I'm a newbie to forums so my apologies in advance for any mistakes.
CAR: I drive a 2006 Lexus LS430 (3UZFE engine) with little less than 250K miles. I am second owner; previous owner did regular maintenance at dealer; Very well kept.
PROBLEM: Two weeks ago I noticed sudden decrease in power / sluggish acceleration after start up. I can bring car up to my desired speed, but requires much more pressure on accelerator. Definitely feels like there is much more travel on accelerator before you feel power engage underfoot than before. When this occurs, car shifts smooth as usual, though it may be a little quicker getting through lower gears than normal.
OTHER ODD BEHAVIOR:
1) I also will occasionally notice a quick drop and recovery in RPM (250-500) when at cruising speeds that I can feel underfoot. It will happen in clusters (2-3 times in quick succession) and then return to where it was uninterrupted.
2) Occasionally it will feel / return to normal (more direct power & acceleration underfoot) for brief period. This "return to normal" seems to happen more often after making a turn, but it will return to sluggish acceleration after I come to a stop again.
OTHER INFO:
1) Car always starts with no problem.
2) No CEL and no codes of any sort (per by BlueDriver OBD reader)
3) Took it to a friend's Toyota dealership; diagnosed for a day. Did a fuel system deep clean and blamed it on failing throttle body assembly. They replaced it with Lexus OEM throttle body, but problem continues. I do not know if they actually checked fuel pressure and I am unable to check fuel pressure with a gauge.
QUESTIONS:
1) What can i look for in OBD readings to help me troubleshoot possible causes?
2) Any suggestions re:what may be causing these issues?
Thanks very much for any help you can offer - cheers!
My problem ended up being the accelerator pedal position sensor. It had worn out and was replaced, Fixed the problem for me and thankfully an inexpensive part and easy repair.
Last edit: 1 year 3 months ago by d.seiple. Reason: Mispelled word
I was able to purchase my part through the local Toyota dealer; I would highly recommend you get an original equipment (Toyota / Lexus) part if you can as this is one of the electronic sensors that helps regulate the speed of your car.
I won't post any links to purchase as 1) I don't know if that's allowed here, and 2) I can't be 100% certain that the part I'm recommending will fix your problem. However you can search on the internet or call a Toyota dealer to order the part.
The part that was ordered and replaced on my 2006 Lexus LS430 was "Toyota 89281-47010". It also had the additional ID number of 198300-3011 (which I believe makes sure that it fits a 2006 Lexus; there are other sensors for Toyotas that have that part number but different ID numbers). It can be variously listed in an internet search but it is going to be called something like "Accelerator Pedal Position Sensor"
You won't find the factory part on Amazon; you will need to look on Ebay if you don't get from a dealer. If you go that route, make sure that the photo of the part for sale shows the "Toyota" name and has the correct part & correct ID number on the actual sensor.
To be safe (if you can't take it to a mechanic or dealer), use your phone camera and take a photo of the plastic sensor that your accelerator pedal plugs into (just follow the wiring harness coming off of the accelerator pedal; it plugs right into the sensor to the left of pedal). It's a very tight fit down there so you may have to take photos of it from all angles and use the flash or a flashlight to help the camera out, but you will find the part number info etched into one of the sides. That way you know all of the information you need to correctly search for your part.
Again, I'm not suggesting this will fix your problem; it's simply what ended up fixing mine. Good luck; I know it can be frustrating.
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