Alright, first post, first problem. 1998 S70 GLT, 150K miles.

Symptoms: Hard to start when cold, now I've noticed oil smell in exhaust while idling.

CEL is on. Codes are 02 sensor related, PO136 and PO144.


Ideas on where to start?, I'm worried it's a compression issue, but car seems to run great. Haven't noticed any oil or water usage. Fuel economy is great and car runs great. Turbo? Or could it simply be an O2 sensor or fuel regulator?

 

I would check the vent system as the first thing.