Maybe it's just bad shift technique/rapidly deteriorating clutch, but I'm having an issue I've never had before. As I accelerate and push in the clutch and let off the throttle to change gears, my RPM's continue to rise for a brief moment. Been driving my car for almosta year and a half and this hasn't happened until recently.

What could be causing this problem?

 

Could be your clutch slipping... Or you are not letting off the throttle completely.

-Mike
www.axispowerracing.net

 

Clutch slippage wouldn't surprise me much. IT works fine for everyday driving, but it is definitely getting close to replacement time when it comes to launching and high RPM shifting.

 

I have the same thing happen on my car, I posted the question on the other forum. If it was your clutch, the RPM's would rise when the clutch is engaged not when you step on the clutch to shift.
It seems it is quite common, but I am surprised to hear that it did not happen until recently. It happens when you shift at about 4k and moderate boost right?
A couple of people tried to tell me it was caused by the flywheel on the WRX being to heavy, but I think that is complete BS, I even consulted an engineering friend who concurred.
In the end it was determined that it is likely caused by a by some excess boost still in the intake after you lift off

 

^^^Thanks for the input. That is the right RPM range. If it is excess boost, then could that be an inproperly working recirc valve? I'm waiting until it warms up a bit to see if ti is onlya cold-weather anomaly. The only time I've experienced it is when it's cold out. Of course, it rained/froze and snowed today, so it will be awhile before I can get some warmer weather to test.

 

(what happened to email notification?)

I have only had my car (MY02) since November and it did it since I bought it. There was a few people on the other forum that posted that said their cars did it too and that it was normal.
I have been having issues with gas mileage (as bad as 11mpg city) and I have been wondering if this is relalted or something

 

I had some bad mileage this last week, too. However I attribute that to long warm-up times with the car running in cold-mode, and the fact that I drive around post witha max speed of 35 mph all the time. No highway driving. I had 14 mpg. Later I took a drive up to Louisville and got my "normal" 18-19mpg. Anyone else have some input on this phenomenon?

All I know is that this never happened when I lived in Hawaii, and didn't happen in Georgia (it was warm) but now here in KY I've had it happen in the cold a number of times.

 

My WRX has had the same issue. The RPM's jump the most when I get on boost in 3rd, 4th or 5th in the low RPM range. For example last night i was in 4th at like 2200 RPM I floored it and then lifted off the gas and pushed in the clutch fast and the RPMs raised to about 3500. When I am higher in the RPM band it does not seem to jump as much. I assumed this happened because the BOV only released the pressure in the intake and not the Manifold and the rpms jumped because of the built up pressure.

My car has about 10k on the odo and has done this every day since I bought it. I thought this was normal behavior... Guess I was wrong.. I am really interested to find out what causes this also

-skooter

 

i think everyone's car does that. its just how you drive your car. when i lift off the throttle and press the clutch simultaniously, the rev jumps a bit. i let off the gas first, then press the clutch.