2007 Jeep Compass Limited, 2.4L, 2WD, Manual 5-speed Tranny, 130,000 miles, original owner

When pressing the clutch pedal to upshift, the rpms increase some 500+. Doesn't happen all the time. Seems to be more prevalent with lower gears and colder temps but not always. Seems to come and go. It's my wife's car so I hardly drive it to know an exact pattern. I do know it has been going on for several years. It's about time I look into it I guess. Not throwing any codes or anything. Thinking possible filthy throttle body and/or IAC or IAT or ABC or XYZ, etc... None of these have ever been cleaned. Before I go messing with anything I thought I'd ask if anyone has run into the same problem Thank you!