1996 saturn EGR

Thanks for the help on the last question. I've got another one for ya. Could a Blocked EGR valve cause the O2 sensors on the engine and the catty to give a false code? I heard that it can. Thanks a bunch for the info!!

Yes, it could be. but depending which O2 faulty codes are displayed.

Which are your 02 codes ?

the codes that are being displayed are p0133, p0141, p0404, & p0300 and I am pretty sure that the EGR valve is the original....its crusty enough to be. Thanks for your help.

Helo

Well, the code P0300.. is a random missfire,, is telling you have a problem when firing the engine. Could you notice if your engine has hesitation, or engine stalling, ?? because with that code it should have.
Then: These P0300 could be produce because the EGR valve. If the EGR is working bad it could produce malfunctions on the engine, so I recommend to inspect if the EGR is working properly and the EGR passages are freeflow, for the EGR code you have I think the EGR valve is faulty.
First we have to resolve the EGR code so then the missfires codes should go out.

Second, the P0133 and p0141 are refering to the 02 sensors.
The P0133 could be related with the problem of the EGR, so don´t change these sensor until you are sure is bad.
The P0141 is not related with the EGR code, it is saying the heater element of the rear post cat ( the oxygen sensor after the catalytic converter ) 02 sensor is not working; it could be a wiring problem but more sure the oxygen has failed, first check if the wiring is ok, if it is ok change the rear oxygen sensor for a good one.

Keep posted ¡