at centerof firewall by blower motor. check vacuum hose for being soft as it may suck together and not give map enough vacuum

It's not in that location on the '90 Bonneville or the '92 Buick Park Avenue. I've been working on a friend's Bonneville and own the Buick with the same engine (3.8L) I can't find the MAP sensor on either car.

that is where it says it is where I told you. the 92 Buick doesn't have one.

Is it possible that the '90 Bonneville SSE doesn't have one either? Only one of the parts stores in town showed the MAP sensor as available for that vehicle and the engine is identical in every visible aspect to the engine in my Buick
.

I guess it's possible I only have what the manual says a car 22yrs old it's hard to remember that far back.