hey guys, im new to here and hope to be a participating member from here on out. I just purchased a 99 es300 with 150k on it, it has about 35k on a new motor replaced by lexus on this so called sludge issue.... when i bought it it had a p0303 stored in it and replaced the plugs... it did nothing then replaced the 3 coil, did nothing, i work at a shop so we ran 5 cans of toyota efi clean through the engine to try to unclog an injector... did not fix it. ended up replacing the 3 injector which fixed the stumble.. then checked compression on all 6 cyl, had 220 on all 6. ran it for a day and set codes for both afr sensor heater malfunctions and ciircuit response malfunction codes, 4 all together, at the same time. then i noticed a stumble in park when revving the engine, does it mostly about 30-45 seconds after a cold start, will not do it when engine is first started. i was able to use the toyota scanner to turn up injector rate 25% which cleared the strumble when revving in park.. my question is... can the afr sensors cause that stumble or are they mainly emissions sensors?? i would not rather replace them right now if i have another underlying problem at hand. any suggestions??
thanks in advance.
chris