2000 Subaru Outback Rough idle and stalls at idle

DLOUTBACK24

MEMBER
2000 SUBARU OUTBACK
4 CYL
AWD
AUTOMATIC
201,850 MILES

I have a 00 subaru outback 2.5. I have been having a continuous problem with the idle. At start it revs to 1200rpm then settles like normal. But when in gear at idle it idles high at 1200 then bottoms out and chuggs feeling like it will stall out and occasionally stalls while in gear aroung 3-400 rpm. I had the 200,000 mile service done by the dealer at 186,000 and have replaced every componet at the manufacturer specified intervols according to subaru's specs. Oil 3,000 trans 15,000 diffs 15,000 etc. I replaced the fuel filter again as good measure and the problem still is occuring. Should I replace the throttle position sensor? Thanks for all the help.

Friday, May 9th, 2008 AT 2:23 PM

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Have you tried cleaning the throttle and the idle air control valve? Or the Mass air flow sensor? Get the sensor safe spray cleaner. Surging can also be a vacuum leak, not out of the question on a high mileage car. Get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!

Was this

answer

helpful?

Yes

No

Friday, May 9th, 2008 AT 2:30 PM

DLOUTBACK24

MEMBER
2 POSTS

Thanks for all the help, I found the idle control adjustment on the throttle body was misalligned, I realigned the control until the rpm changed while in gear and at idle. I tested for vaccum leaks and found none. I think I figured it out but would it be best to replace the sensor to ensure no more issue or leave my adjustments.

Was this

answer

helpful?

Yes

No

+1

Friday, May 9th, 2008 AT 7:21 PM

MERLIN2021