i have a manual transmission on my 04 aveo with 152,000 miles
i have to keep downshifting to maintain speed (power) especially up hills
and it is slow to accelerate
starts fine
idles fine
no check engine light at all
never serviced the tranny or fuel filter
can anyone help with what to check before i send it to the garage?
the mechanic said to look for obvious things and he thought a small animal might have made a nest in it
thanks