97 mitsubishi bad radio reception

FM need a good antenna, buT FM in the country side will be weak
or even dead, FM does not travel far at all ,even only 20 miles
AM we have super power stations that cover most the country.
I bet the RADIO is just fine.
it can be bench tested with a 1 strand of say 4 feet of wire for an antenna.
you posted about only a RADIO not CD and not AM
FM is short ranged, 88 to 108MHz. is that
no town told , but you can call your closest station and ask them there coverage, spec.? 50miles or 10 or? what ever.
or you can go to a 2nd car, test FM see if there is one strong station.
if not there there is none.
on home RADIO we use a roof mounted 30Ft high antenna, FM
and goes way father,.
in car that can not be done, most antenna amps in cars only increase noise.
is this your first car, or first ever FM radio.?
yes antenna's can fail even the ground, (it is 2 wire coax to fail)
the mount can corrode. the cable can be bad.
some have antenna in the wind shield glass, and some one puts in new glass with no antenna there well that fails hard.
FM is mostly a CITY BIG DEAL, no living in the sticks.
also there are tiny FM micro station,and those are weak.
only line get a FM map for you town, just like Cell phones but for FM.
radio. see what is there and its POWER/coverage.

Most likely the antenna lead has come unhooked from the back of the radio. AM stations will pick up with the internal working of the radio, but FM stations have to have a working antenna to work. Also make the antenna is tight to the vehicle .

A.m. radio stations have a very limited range and honestly modern units include am reception as an after thought. Unless you are within a few miles of the station you probably won't pick it up. That being said if you are close enough and still cannot pick it up then the radio is probably faulty.

If you pick up FM. It isn't the antenna. It's an internal radio problem.

Check the antenna connections.

I had the same exact problem. Toyota changed the Amolifier that improved sound quality but not the FM Reception.

THE HARNESSES CONNECTING ANTENNA TO RECEIVER (TWO OF THEM) HAD IAASUES. REPACING THEM FIXD THE ISSUE. FM RECEPTION EXCELLENT NOW !!!!!!!

YOU MAY HAVE A PROBLEM WITH THE ANTENNA. THERE ARE 4 ANTENNAS IN THE REAR WINDOW FOR BOTH AM AND FM SIGNALS. THERE IS AND UNIT CALLED A DIVERSITY BOX UNDER THE REAR HAT SHELF THE CONNECTS THEM ALL AND DECIDES WHAT ANTENNA IS GETTING THE BEST SIGNAL. THAT UNIT MAY BE FAULTY. BEST TO HAVE IT CHECKED BY SOMEONE WHO KNOWS THE SYSTEM OR TAKE IT TO A DEALER. MIGHT BE CHEAPER THAN BUYING A NEW AFTERMARKET RADIO.

I’m happy to help further over the phone at https://www.6ya.com/expert/anthony_dda4e0152e94f3c0

check radio antenna. could be loose connection or antenna missing or broken.

do you get any stations, even weak stations on the AM band?  If not you have a bad radio and need replacement.  Try having someone hold the antenna as you scan the AM band.

FM radio reception relies on a very good working antenna and cable, AM reception much less so. Unfortunately, the problem could be in the radio itself as there are separate signal processors in it for FM and AM. However, the most common problem is a bad cable connection at the antenna or the radio, or a bad cable itself (corroded, pinched, broken wire inside).
.
A couple of simple things to check: if the antenna is in the window, it may have become disconnected from the cable at the window. If the antenna is body mounted, could be a bad cable connection at the base of the antenna, and in this case, the base of the antenna could be very corroded.

You could also check the antenna cable from end to end using a continuity checker. If you can't figure that out, you could just try replacing the cable (or body mounted antenna in that case).