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Hi there,

 

I changed the battery on our Subaru Legacy L (2000) last week and now the car can't hold a constant rpm at traffic lights etc. The needle slowly falls to about 100 rpm before bouncing back up to around 900 rpm. My mechanic says its probably just the throttle body that needs cleaning...does that sound right?

 

Cheers

 

Bespoke76

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Could be lots of things, but prolly just a coincidence and not related to the charge ... unless, you didn't hook the charger up backwards along the line did you?

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If the battery was diconnected long enough it might have reset the ECU and its having ti re-learn the idle setup... just a thought.

 

Gary

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Charge the battery again and see it the problem goes away :lol:

 

My money's on two different problems. If your talking about your original battery, it's now 5 years old and probably getting to the point of needing replacement anyway.

 

Two things, I'd try

First a couple of bottles of carb/injector cleaner through the fuel system over the next few weeks.

 

Second check your antifreeze level? My trooper will idle funny, (high & low) at the intersections when the antifreeze level get low.

 

Good luck,

Glenn

82 SubaruHummer

01 Forester

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I agree with All Talk about the ECU. The owners manual talks about the learning procedure I think.

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Before resetting the ECU (which involves disconnecting power), just try starting the engine and letting it idle for about a minute. Then drive off.

 

This might do the trick.

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Hi there,

 

I changed the battery on our Subaru Legacy L (2000) last week and now the car can't hold a constant rpm at traffic lights etc. The needle slowly falls to about 100 rpm before bouncing back up to around 900 rpm. My mechanic says its probably just the throttle body that needs cleaning...does that sound right?

 

Cheers

 

Bespoke76

Did you disturb any vacuum lines in the process of replacing the battery?

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Before resetting the ECU (which involves disconnecting power), just try starting the engine and letting it idle for about a minute. Then drive off.

 

This might do the trick.

 

Disconnect the battery for approx 1 minute. Reconnect it. Make sure ALL accessories are off (lights, A/C, stereo, etc). Start the engine and DON'T TOUCH ANYTHING---DON'T TURN STEERING WHEEL--KEEP FOOT OFF OF BRAKE PEDAL--JUST LET IT IDLE FOR APPROX 60 SECONDS IN "P" (nuetral with stick shift) to re-learn the correct idle speed.

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I think the general consesus for a battery dance is a minimum of fifteen minutes (to an hour). BTW, open a window and leave the key in the ignition, that way you won't even turn on the dome light when you start it.

 

When you start driving, drive the way you want the car to perform, it will 'learn' your style, aggro, benign, wimpy, and respond that way henceforth.

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