When I try and boost in my 08 WRX, the rpms jump from 3000 to 3500 and then back to 3000 before picking up speed. I have been told it is my clutch slipping but i would like other opinions. Please tell me what you think!!
Unless you are getting wheel spin, yes I would suspect a slipping clutch. You might try a clutch test. Move the car up to an immoveable object like a tree; set the parking brake hard; put the transmission in the highest gear; rev the engine; as you lift the clutch pedal give the engine gas as if you are launching. If the clutch is still good the engine should immediately die when the pedal is fully up. If the engine stays running, the clutch is slipping. Do not extend this test more than a second or two because you are going to need to baby the clutch until you can make it to a shop.
That plastic bumper is not going to look pretty after you attempt this.
This maybe is a good method for a car back in 80’s or before but anything with fiberglass bumpers that you care about awful.
You don’t need a tree to do this. As andrew j suggests, it will damage the car.
Setting the parking brake firmly is sufficient for the clutch test.
However, if the clutch were slipping and you tried to accelerate hard while driving, the rpms would shoot up and probably stay up. Why they are falling back to 3K I can’t explain.
How many miles on the car, and how hard do you drive it?
I am more inclined to believe you may actually have something wrong in the turbo plumbing. There is a waste gate actuator and few other parts that if sticking can cause symptoms like yours. A check engine light usually comes on but not in all cases.
Does this car have <60,000 miles. If yes visit your dealer as this is likely covered by the powertrain warranty.