2000 RX300 AWD with 61K on it.
Each morning when I start the car and put it on road immidiately, it runs smooth like it used to be. Gear shifts up all the way to overdrive while speed goes up. At 50MPH, the teco shows 2000RPM which is normal.
But it will last for only couple of minutes.Once I slow down then speed up again it won't shift to the overdrive back no matter how fast i go. That's about 2600RPM at 40MPH, 3500RPM when I drive at 60MPH. MPG drops to 14MPG from about 17MPG(suburban local drive) sicne two weeks ago.It normally happens when the collant tempracture reachs normal(take about 2 minutes). When it happens someehow the engine lucks of power a little bit ---- the idle is still smooth and steable, no engine knocking was heard even step on gas hard.
The check engine light has been on for a while (7 or 8 of months say). The car was running fine untill recently...I took it to autozone, the scanner shows P0171 (bankone too lean) and P0330 (knock sensor or circuit out). I switched the MAF with my 2000 Avalon (same engine) and the P0171 has gone, but P0330 remains.I also had the transmission flushed at Firestone at $200.
The other day I have a transmission shop scaned my car use there $6000 scanner....no transmission error code, P0330 is the only one can be found.
I also took it to 3 workshops, someone says it was due to a bad timeing belt replacing work, timing belt/water pump needs to be replacd again. Another guy from another garage told me the engine might be missfire (he did a test drive only, no tools used.He draws the conclusion based on the lack of power when press gas.).
I also called my local Lexus dealer. They told me the chance of knock sensor going bad is small...they only carry ONE knock sensor in stock , that kind of proved what they said....also, from this forum and someother forums, people also mentioned that knock sensor wires could go wrong...
I was trying to purchase a knock sensor harness but was told "no such thing available"
Need some suggestion/diagnost before heading garage spending $600 to $1100(this is what dealer told me if they need replace both knock sensors)
Any comments will be highly appreciated!!