My rx300 has 250000 miles and ran great (except idle) Now it makes a loud hum n on 1999 Lexus RX300

noise. Acts like it is not gettin fule. I changed the gas fule pump and filter but it did not help - can anyone out there help - thank you. Diagnostic shows nothing wrong???

Asked by for the 1999 Lexus RX300
Broken/jumped timing belt.? what other symptoms?Did you test the fuel pump before replacing it? Check fuses ECM1 & ECM2(or may be labeled EFI)
I replaced the mass air fule sensor - did not work I had it towed 100 miles to the dealer - hope to hear from them today and will post the results

Thank you so much for taking the time to held

Just heard from toyota dealer said it's the "air fuel ratio sensor" $400 parts and labor thanks again