My factory installed mass sensor went bad, (car dies right after start up, won't restart, unplug it and starts fine). So I purchased a generic sensor that was supposed to work for my car, (98 S70 T5), $96. After installing this generic, on first turn of the key the engine sputters and dies, (raw fuel smell from exhaust). On second turn of key the car starts perfect and runs perfect, (I think even better than before the original went bad). There are no engine codes.

Is there something I missed in installing it? or, do I simply get what I pay for?

 

I think you got what you paid for.
Also was it the entire housing or just the insert?

 

it was the entire housing. I have also now noticed that if I floor it while going about 70mph, it sputters like it's starving for fuel.

So am I safe buying a Bosch replacement or do I need for get a factory replacement?

 

Bosch is fine since it is OEM.

 

I bought a Bosch and it works perfectly. Never ever buy one from "Auto Parts Place", it will not work.