Bad Idle

Kensubguy · 06-06-2005, 09:35 AM

Over this weekend I attempted to reset the ECU on my 99 subaru Legacy. During this morning drive to work the idle seems to have gotten worse and the car seemed to almost want to die down and then pick up the rpm. It had one big pulse down but then would even out and smothen. I wonder what the issue might be here.

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kpalena · 06-06-2005, 07:41 PM

omg....

There are tons of things that could be going on here.

It could be:
coolant temperature sensor
bad injector
Dirty MAF
Really dirty air filter
bad egr valve/sensor
Throttle position sensor.

First try to answer the following.
Are you throwing a CEL?
Does it start hard?
Does it do it when warm?
Does is accelerate poorly?

This is a common and tricky problem. I have learned a lot from this forum. Look around and see what you come up with.

tora · 06-06-2005, 07:54 PM

Keep driving it, my guess is it will sort itself out as the ECU is re-learning.

Kensubguy · 06-07-2005, 10:51 AM

The Idle has smoothed out but I am having a hard time going up hills now. Today I could not get to 40 mph which I normaly does. I have a persistent CEL and been planning for 2 weeks now to change the oxygen sensor and the knock sensor. I had a code on knock, fuel/air metering and idle sensor malfunction.

EastsideLegacy · 06-07-2005, 10:45 PM

Im not tryin to steal the thread but im having hesitation while accellerating in 2nd and 3rd gear at like 3500 rpms ... any suggestions( replaced the wires and coilpack )..

thanx main

06-06-2005, 09:35 AM	#1
Kensubguy Scooby Newbie Member#: 84082 Join Date: Mar 2005	Bad Idle Over this weekend I attempted to reset the ECU on my 99 subaru Legacy. During this morning drive to work the idle seems to have gotten worse and the car seemed to almost want to die down and then pick up the rpm. It had one big pulse down but then would even out and smothen. I wonder what the issue might be here. * Registered users of the site do not see these ads.

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06-06-2005, 07:41 PM	#2
kpalena Scooby Specialist Member#: 82431 Join Date: Mar 2005 Chapter/Region: NWIC Location: Battle Ground, WA Vehicle: 2006 06 wrx limited CGM	omg.... There are tons of things that could be going on here. It could be: coolant temperature sensor bad injector Dirty MAF Really dirty air filter bad egr valve/sensor Throttle position sensor. First try to answer the following. Are you throwing a CEL? Does it start hard? Does it do it when warm? Does is accelerate poorly? This is a common and tricky problem. I have learned a lot from this forum. Look around and see what you come up with.

06-06-2005, 07:54 PM	#3
tora Scooby Guru Member#: 5851 Join Date: Apr 2001 Chapter/Region: VIC Location: Vancouver Vehicle: 09 Forester XT + NA Miata	Keep driving it, my guess is it will sort itself out as the ECU is re-learning.

06-07-2005, 10:51 AM	#4
Kensubguy Scooby Newbie Member#: 84082 Join Date: Mar 2005	The Idle has smoothed out but I am having a hard time going up hills now. Today I could not get to 40 mph which I normaly does. I have a persistent CEL and been planning for 2 weeks now to change the oxygen sensor and the knock sensor. I had a code on knock, fuel/air metering and idle sensor malfunction.

06-07-2005, 10:45 PM	#5
EastsideLegacy Scooby Newbie Member#: 58806 Join Date: Apr 2004 Location: New york Vehicle: 1998 RIP Legacy2.5GT 2.2L legacy wagon	Im not tryin to steal the thread but im having hesitation while accellerating in 2nd and 3rd gear at like 3500 rpms ... any suggestions( replaced the wires and coilpack ).. thanx main