2003 Saturn L300 Question: My Saturn is losing power at 4000 RPMs

Our 2003 Saturn L300 (V6) is losing power at around 4000 RPM. If I release the gas and let the RPM's drop it seems to re-engage. Our service light had gone on and we took it to AutoZone for a free diagnostic but they said it was just time for a tune-up. I called a garage and they said tune-ups are a bit too general now a days and that it actually sounded like their might be a hose of some sort needing repair. It would be great to get some advice before we take it in.