I brought back from Europe my 1998 millennia to the states . In Europe it stayed idle in a garage with the tank full of fuel from 2011 to 2017 . I brought it back to the states and a short time after that it developed. A sluggish acceleration around 20 - 30 miles per hour after that seems to run fine . I changed the gas filter still same problem and new tune up with no results could it be the jets are clugged please help .
Did you drain that old fuel and put fresh fuel in? If tried to crank it with that old fuel I wouldn’t be surprised if you’ve clogged up the fuel system