Gs300 Engine Misfire

[monk]

hello all,my 1999 gs300 has developed an intermitant misfire,my local toyota dealers, diagnostics revealed suspected oxygen sensors were faulty all four of them codes po135,po141,po155 and po161.they said it was unlikley that all four had gone ,there diagnostics couldnt get any more info and said i would be better off going to a lexus dealer.before i do does anyone have any sugestions please.

[steve2006]

Hello and welcome to the LOC.

Surprised at the diagnosis, I would sta.rt with the basic ignition component checks, spark plugs and coil packs

[monk]

tested all the ignition stuff,theres no warning lights on the dash which seems a bit odd.its looking like a trip to a lexus dealer.

[ColinBarber]

The 1998 - 2000 GS doesn't have a compliant ODBII socket so many diagnostic tools are unable to correctly read the error codes.

It is possible to obtain codes by shorting pins on the socket and counting the flashes on the dashboard. Here is an example of this being discussed in the past:

http://www.lexusownersclub.co.uk/forum/topic/83528-diagnostics-99-gs300-uk-spec/