CEL on 1999 ML430 with 115,000 miles turned on with P0130 (before cat O2 sensor, bank 1) and also showing P0301, P0304, P0303 and P0300 codes.

CEL reset 30 miles ago and has not yet turned on again. Vehicle is starting and running smoothly, no stumbling or hesitation and no unusual smoke out the tailpipe. Fuel economy (well not really economy) is normal. MAF was replaced 50,000 miles ago and plugs (Bosch Platinum +2) at 100,000 miles. Burning 93 octane fuel.

Anyone suspect this is a problem with something other than an O2 sensor that is failing?

Thanks.

__________________
Jim