New To Forum - Looking For A Mechanic

[dopenaut]

I purchased a 1999 ES-300 back in 2006. I've kept up with maintenance over the years. It currently has about 100k miles. I had timing belt changed soon after purchasing at 86 k miles. About 6 months ago Chk/Eng and Trac Off lights came on. And overdrive would occasionally stop working. After a while it stopped working all together. I've taken it to a few trustworthy mechanics that I have used over the years but none could ever fix the problem. Many oxygen sensors have been replaced, knock sensors, temp sensors, thermostat. You name it. One transmission place said I needed a new transmission, another one said the transmission was fine. So finally I took it to toyota dealer (expensive). They said OK you just need a fuel system cleaning. I said wonderful. It didn't work. I've been driving the car without overdrive (trying to stay local and below 45 miles per hour). NOW the engine is knocking so bad I am afraid to drive it. I can't really afford to take it back to toyota or lexus since I'm currently "between jobs". Is there a retired Lexus mechanic out there that can help me diagnos this problem? I really do love the car but unless I can figure it out on my own, I'll just have to trade it in. It's so frustrating.