Would mayo and peanut butter be okay to eat if left in the car?

If they were 'unopened', yes, they're fine. The peanut butter would be fine even if it was opened.

If the cans were opened the peanut butter should be okay to eat, but the mayonnaise probably isn't safe to consume. If the cans weren't open at all then the peanut butter is fine, but I wouldn't risk the mayonnaise.

I would not ever. BUT and I swear you HAVE to do it this way...grilled cheese sandwichs made with mayo instead of butter. My dad always made them this way because back in the day butter came in a stick not a tub and it was hard as a rock. But grilled cheese with mayo is delish and much more hearty tasting than when made with butter. Does anyone else do this?

If the car's interior got hot peanut butter would still be all right, just runny until it cooled off.

But if the jar was hot, I would NOT use the mayo (sealed or not), since its base ingredients include raw eggs.

Just wondering why on earth you would have 2OPEN jars of peanut butter and 2 jars of mayo in the car??? Anyone else think it's strange?

yess but just look at the expiration date and if it is open and how long it has been in that car.