Information gleaned from in other threads (using my mind's gleaner--not the carpet cleaner instrument-- haha):
1) cleaning or replacing worn fans
2) checking the hose inlet seal for deterioration and replacing if necessary
3) replacing the air filter located on the inside of the exhaust port
4) replacing the filter bag (the rubber seal may be worn)
5) performing the bubble test on the hose: lightly squirt a mild cleanser such as diluted dish soap on
the hose, then connect the hose to the exhaust port of the cleaner, turn it on, and cover the end of the
hose with your hand. Bubbles will form wherever there are leaks.
6) checking the hose for obstructions by passing a golf ball, quarter, or other small object through the
hose; connecting it to the exhaust port and putting the handle end in the intake port.
7) checking for and removing any obstructions in the bag chamber
I have a Model XXX, and the suction is pretty good, so unless your motor is deficient in some way you should be able to strengthen the suction power with the above suggestions. Best wishes.