I have a 2000 RX300 with 98k on the odo, during this summer it ran like a breeze. However, once winter started to hit (In Alaska with average temp in teens) the engine began to knock severely like the rocker arms were hitting. I changed the oil again (mobil 1 filter and penzoil platinum 5w-30 full synthetic), still running like crap, very sluggish, lost performance, gas mileage info down to 14.4 mpg avg. Today I went through and cleaned the MAF and added Chevron Full Fuel System Cleaner with Techron to help clean the fuel injectors. So far its a little more smooth but still sounds like a deisel engine, this knock does not go away while accelerating but is most noticable during idle in nuetral.
There are no check engine lights on. Tomarrow I am going to clean the IACV and get an oil additive. So far there has been no noticable oil consumption, residue in the oil pan, or oil going through combustion. I think this might be an 02 sensor or Air Fuel Sensor issue but don't know how to check because of the lack of check engine light which I think means lack of error codes.
I would really appreciate any help.
