I just changed the knock sensor on my lexus rx 300 now the second and third gear dont have a smooth change also gear all of a sudden is not going into the 4th gear

Yes, looks normal, and good. Calculated load is not much meaning, as it changes constantly. ECT of, oh that is centigrade, not sure how that translates to Fahrenheit, but it may be low from not running long...
Your fuel trims (both short term and long term-STFT, LTFT) are very good-showing that fuel is not being added or subtracted by the computer to maintain correct air/fuel ratio. Fuel trim numbers should be close to zero. It is when fuel trim changes by double digits-either positive or negative-that there is an indicated problem. For example, say you had a vacuum hose leak- sucking in extra air to the engine- then you could see STFT number go positive by double digits-meaning the computer senses a lean condition and is adding fuel to compensate. But your fuel trims show the air/fuel ratio must be correct-no change in fuel trims-the positive 2.3 in LTFT is negligible- not a problem.

code p 0330 refers to knock sensor (KS)2 bank 2 ---circuit malfunction===causes wiring--KS---ECM
it is possible that in changing the harness there is a problem connection or the connection to ks2 is not correct ( not on properly)

You have 2 of them,here's a link showing where their at,once you get to page,click on switch and relay. SENSOR KNOCK CONTROL 176 07 Fits LEXUS RX300 1993 2005 Part 8961512090... Here's a video showing you where they are at. 2000 Lexus Es300 Knock Sensor Location Repair

Here's a link on replacing your knock sensor. RX300 knock sensor replacement DIY Club Lexus Forums

does the third brake light work? If so change bulbs on lower lights by removing cover then taking out bulb. It twists out. Simple.

some are on the cylinder head or on the side of block . they screw in .

remove intake manifold and air intake chamber completely, the knock sensors are located in middle of engine

I'm not a lexus guy , but I'm thinking that you have a vacuum leak somewhere.

better get another mecanic as the motor is the same as a toyota 3.0 lv6....scary

$700

timing belt
idler pulley
water pump
timing belt tensioner
valve cam gasket
coolant flush
spark plug
oil change
pcv valve
tranny oil change
differential fluid cahnge
drive belt
upper/lower radiator hose
brake system flush
air filter

good luck,i hope this help pls dont forget to rate me thanks