02 sensors
 

1997 SL600 V12,
Had a used motor install at 75,000 miles since then has been throwing codes P0135, P0130, P0155, P0150, P0141 and P0136, I have replaced 3 sets of 02 sensors. I had 3 different shops test my car and all said they would bet I replaced a ton of 02 sensors but had no idea why, I have replace both catalytic converts and three sets of 02's

I was reading some data on the ECM it sends the different levels to each component, it appears that maybe this is the issue not the 02 sensors.

Anyone out there have any suggestions ??

did you check vacuum hoses and pump, connectors, wiring?