Ah, interesting!
Like Rallycinq says, maybe yes, maybe no.
The only thing that's pretty certain is that it's not a lambda fault. A scattergun approach isn't likely to get you anywhere fast, and, if you don't have access to a supply of sensors, it'll cost a packet.
Rallycinq has posted a list of the nominal values of the SPI sensors on ClubCento (in the member's section) -- you just need a bit of time and a tester to run through them.
Alternatively. if you can get the buggy to a local FIAT dealer you might find that someone there likes it enough to run a diagnostic on it for nowt.
But don't hide your light under a bushel, some details, please, and pics!