RST Engineering wrote:

The OP said this was a 172.

Some are. So I have to ask.

Anyhow, if so it may be linked to a problem in the fuel pump. Mine was
actually missing a connecting spring (from factory) that did not allow
it to maintain a fuel flow at idle settings. So for years I go around
with it a bit high on the idle and sometimes on rollout, just at the end
and starting to turn off, the engine would shake and I would hit the
electric pump to bring it back. I actually had it down to a fine art.
The problem was only found when the pump was pulled and sent out to have
a seal changed.

John