1999 V70, 85,000 mi. - O2 Sensors & Speedometer Problems

[KevCan]

Howdy,

My problems began shortly after buying this car....check engine light and $100.00 diagnosis says O2 Sensor. Replaced both with Bosch Universal type. Seems like post cat is ok but keep getting check engine and code for pre cat. Changed out pre cat with same Bosch Universal but still getting check engine. Is it true that the Bosch Universal just aint gonna work? Speedometer problem is just one symptom of problem that is intermittent...sometimes there is no speedometer, or info displayed in dash...sometimes it comes back on in a while or will work fine on next startup....weird....any clues welcomed. I really love this car but its killing me because it is used mainly by my wife and she is constantly complaining about these things....I guess if I cant afford to take it in for repairs then I probably should not have one...I'm gonna try to do the repairs myself and hope that I will find some nice folks here that might offer guidance. Thank You...Respectfully, Kevin

[MadeInJapan]

Kevin,
Take it to a good non-dealer, Volvo mechanic. Typically, vacuum hose leaks will show up as front 02 sensor issues...among other things.
The dash lights on and off, etc. could be your ignition switch. Next time when this happens, try jiggling your key in the ignition to see if this is it.