01 Subaru Legacy L 5-speed Engine Revs when gas pedal is untouched

When I first start my car I let it sit for 1 seconds, then I reverse out of my driveway, once I am at the bottom of the diveway I hit the clutch and break but my engine goes from 1.5 to 3k RPM I am not hitting the gas pedal at all then I drop it into first and it goes back down, when I go from 1st to 2nd while i have the clutch in the RPM rise. I am not noticing any thing else wrong with the car and wondering if this is a sign of another problem. Basically my cars engine revs even when the gas pedal is not being touched. I have checked to see if there is something down near the pedals that could cause it like a mat getting in the way, but there is nothing. I had a friend who is a mechanic hook up a diagnosis machine to my car and said there are no computer errors. Just wondering if anyone else has had this problem and what the solution is and if this is a symptom of a worse problem.

SOME legacy’s have a clutch CABLE…while others have a Master and Slave cylinder Hydraulic setup… I am curious to know which system you have… I am thinking that you might have a cable…and if so it is possible that it could be routed in a way such that when you tension your cable it can pull on or interfere with your accel cable… LOOK into this possibility ASAP please… this does not sound like a condition to ignore AT ALL.

This is the only thing that I can think of that would tie these two unrelated things together… The OTHER item…would be your floor mat…and the way Subaru has the accel cable hooked up near the floor… Make sure there is nothing interfering with the accel cable or pedal in association with your clutch… ALL good things to look into ASAP…Please check into these two possibilities.


The car may have an Idle Air Control valve and/or throttle plate problem and these can occur while leaving no codes. The IAC is what controls the engine idle speed and it does this with input from the ECM, or the car’s computer.
As to the throttle plate, that can hang up due to intake tract deposits or in some cases, wear on the throttle body.

If you’ve ever heard of the induction system cleaning process then that process is what can clear this up. In some cases the IAC may be faulty and needs to be replaced.

Of course I agree with you about the AIC OK44…and also on how it works…spot on… but I was trying to tie the clutch being depressed with an increase in RPM’s tho… What, if anything do you think ties those two together? …the AIC has no idea what the clutch is doing … The issue also seems like it is repeatable…What else could this be?

Wait maybe he has a vacuum leak? I re-read the post and maybe I tied this too strongly with the clutch being depressed…

Do the RPM’s rise every time you push in the clutch…I mean can you repeat this in the driveway? If not it may have nothing at all to do with the clutch and like OK44 mentions…that AIC is what controls the whole show when it comes to idle

You need to do a little test for us…
What does your car do when you just start it up and let it idle? What happens when you push in only the clutch… also when only the brake is pushed?.. Savvy? Let us know…bec if this is tied to you pushing in the clutch then it sure is weird…and the only thing I could come up with would have been a clutch cable interfering with the accel cable… But maybe the AIC is just acting up and you are mistakenly tying this surging to what you happen to be doing at the moment… Try doing the tests I asked for and let us know…

Start from cold and let it idle for say 2 minutes… Does it surge at any point?..Perhaps it will surge when you start to warm up a bit…like after 2-3 min… If it begins to surge after a few min its the AIC…and the AIC is strongly tied to the coolant level and no air pockets being in the system…

“I let it sit for 1 seconds, then I reverse out of my driveway”

Try letting it idle (cold) for 15-30 seconds before putting it in gear.
Give the computer time to establish a stable fast idle.

Exactly what I wanted to see…circuit. We need to know if the AIC can do its job here…and don’t know what the idle quality is like…going from cold and transitioning to warm and hot…

We need more info please