1998 Volvo S70 inspection

PO130 is for the front heated oxygen sensor signal faulty or missing and 172 is for long term fuel trim part load but dont know if it is running to lean or running too rich unless you can actually get it scanned to read off what it is? But for this 2 codes you should be looking for an intake and exhaust leak. Either one will give you a faulty oxygen sensor reading and fuel trim readings as well. If visually you cant see any damaged vacuum lines you would need to have the intake system smoked tested to see if the intake has a leak. For the exhaust system if no missing or loose nuts are found and you dont see any signs of an exhaust leak , then you would need to have it pressure tested and spray some soapy water around all the gaskets like the manifold and flanges before the the CAT. Behinde the CAT it does not matter if you have a leak or not. If you do find leaks with this tests, after the repairs you need to make sure the fuel trim adaptations are reset as well or the codes will come back on. If all that looks good then you will need to replace the oxygen sensor for the faulty signal and the mass air flow sensor for the fuel trims and reset the adaptations as well. Also what State are you in? If you are in California and you were directed to a test only station you can apply for the consumers assitance program where they will help you out with as much as $500 in repairs. But you would need to apply for it and once you get approve, take it in to a Gold Shield Station. Here is the link where you can download the application if you are in California.

http://www.bar.ca.gov/80_BARResources/01_CAP&GoldShield/Factsheets/Consumer_Assist_FAQs.html