Has anyone out there with '06 Tacoma/AC/2.7L/4AT/2WD ever experienced annoying engine clicking or knocking noise coming from engine or underneath the cabin? I've been hearing the noise and complained about it to Toyota Executive office in California since I bought the truck back in Feb this year. They told me that a fuel line problem existed in March but never contacted me again when the TSB was issued in May. I found about the TSB in this forum, thanks to Ampeg's thread. I finally took it to my local dealer this week and they installed a fuel return hose but the noise never went away. It is hard to describe the noise but it sounds as if my truck is dragging a steel chain all the time. The noise is especially annoying when the engine is still cold but because of the constantly revolving engine fan even from the moment I start engine despite the coldest temperatures just prevents it from fully warming up even after 20 miles of driving to my office every morning. How come the fan is not controlled by the thermostat like other cars? This noise stops only when I remove my foot from the gas pedal. It also emmits another mechanical noise when it's very cold which sounds like a playing card against the moving bicycle wheel spokes or someone trapped in the engine room is banging the engine block. To be honest with you, my 10 year old Ford Taurus runs better and I'm one dissapointed owner of Tacoma truck that I was so excited to buy 8 months ago. Any advise on these issues will be appreciated.