Yes, off-hand I'd say don't drive @ 45-48 mph!

Sorry, but I couldn't resist.  Well tell me, if you've run most of the fuel
through.... then why not top off the tank to freshen it up?  Also how is
your fuel filter?  Has it been changed recently?

Sometimes gunk can form in the lines and tank during the winter.... and
this stuff will collect in the filter itself.

So that's what I'd try first...... new filter and fresh gas.  If that
doesn't work, then try other stuff.

Regards,
Shawn.