Scooby96 Posted February 4, 2009 Share Posted February 4, 2009 (edited) My 96 Outback 2.5 recently started to idle very rough right after I start her up (hot or cold) almost like she is going to choke out (lasts approx. 10 sec) then it would rev up to 2-3000 rpm for a few seconds before finally reaching a normal idle of about 1000 rpm. This happens every time I start the car and some episodes are worse than others. Once I'm out of the driveway there are no problems until the next time I try to start her up. Idles fine at traffic lights, drive-thru's, etc.. Problem started about two weeks ago so I checked out the plugs (which were fairly new) and they didn't look great so I replaced them. This seemed to fix the problem but only for about a day or two. Problem came back, A little worse now so I pulled the plugs again and again the plugs looked fouled. Replaced, better for 10-15 starts and now it's back. Also replaced the air filter, fuel filter, oil change , coolant change, and PCV valve. Any thoughts. Edited February 4, 2009 by Scooby96 Quote Link to comment Share on other sites More sharing options...
lmdew Posted February 4, 2009 Share Posted February 4, 2009 Any Check Engine Light? Sounds like you may have a leaking fuel injector. Are all the plugs the same color? How long do you have to wait between starts when it does this? Minutes, hours, overnight? Quote Link to comment Share on other sites More sharing options...
86subaru Posted February 4, 2009 Share Posted February 4, 2009 some things that might help, clean out the idle air control, check or replace coolant temp, seafoam in the tank, clean mass air flow, these things may or may not be the cause but could help, and the car will run better, Quote Link to comment Share on other sites More sharing options...
Scooby96 Posted February 4, 2009 Author Share Posted February 4, 2009 Thanks for the quick replies. Imdew, I did have a check engine light about 3 days ago, took it to auto zone and the codes read misfire of piston 3 and 4. Had to disconnect the battery to change the plugs on that side and the light has not come on since. I have had the car for about 4 yrs now and the check engine light has been a regular occurance with the same misfire codes. The second time I pulled the plugs I only replaced the left (looking at the engine) 2 because they were the easiest to get to and I was short on time. They both looked ashy and almost like they had some sort of crystal like deposit on them. When I changed these two it got rid of the problem but for only a short while. I have yet to look at the other two. As for the wait time, it doesn't matter it does it every time. When I crank it cold it does seem to be a little worse. Quote Link to comment Share on other sites More sharing options...
nipper Posted February 4, 2009 Share Posted February 4, 2009 i'm tempted to say its a bad coolant temp sensor. Quote Link to comment Share on other sites More sharing options...
Scooby96 Posted February 5, 2009 Author Share Posted February 5, 2009 Do I have to drain the coolant in order to replace the coolant temp sensor? I just have such a hard time trying to get the air out of the syst after I refill it and I did this about a week ago. Quote Link to comment Share on other sites More sharing options...
msmithmmx Posted February 6, 2009 Share Posted February 6, 2009 When the check engine light comes on does it blink for a little. With 3 and 4 going at the same time I am going with a bad coil pack. I had this same issue last week and I replaced 200K coil pack. Problem solved. And please Ebay that coil pack or ask on the board here. You should be able to get one for under 20 bucks. The dealer my guess is 3 bills Quote Link to comment Share on other sites More sharing options...
Scooby96 Posted February 6, 2009 Author Share Posted February 6, 2009 Yes, when the check engine light came on it was blinking, but since I changed the plugs about 5 days ago it has not come back on yet. would a bad coil pack cause it to idle rough at the start up. I am going to try to clean the idle air control and the mass air flow this weekend if I have time. Do you guys think that would be the easiest place to start? One last thing, 2 days ago I had absolutely no problems whatsoever with the idle, but yesterday they started acting up again. So it went from bad idle one day to fine the next day and back to bad idle the day after that. Any thoughts? Quote Link to comment Share on other sites More sharing options...
abog Posted February 6, 2009 Share Posted February 6, 2009 When you refill your cooling system, fill the block through the upper hose, put the hose back on the radiator and fill the radiator. Remove the small plug on the top of the radiator on the opposite side of the cap. Add more coolant until it comes out of the small hole put the plug back in and you are done. Put the correct amount in the overflow when warm and you shouldn't have any:) air pockets...... Quote Link to comment Share on other sites More sharing options...
crash321 Posted February 7, 2009 Share Posted February 7, 2009 To answer question about draining coolant, no you don't but you have to unscrew the sensor fast and screw in the new one fast , you will lose little coolant this way, just top off if need be, second, no one has mentioned whether the condition of the wires are good or not, pull the wires off of the coil and look for burnt discolored terminals. They should be a brassy color with no discoloration. Also are you using NGK plugs. Subarus are finicky with their plugs and wires, make sure they are Subaru OEM. Also coolant temp sensor was mentioned, If it has gone bad, the car may think it is cold when it actually is warm and dump more fuel into the cylinder cause black smoke out the tailpipe. It is easy to test with an OHM meter. The OHM values may be in a haynes manual. Also, you may have a bad fuel injector, but that would only affect one cylinder, so not likely your problem if your are fouling all your plugs. Check these items and more than likely you will find your problem. Good luck:) Quote Link to comment Share on other sites More sharing options...
Scooby96 Posted February 7, 2009 Author Share Posted February 7, 2009 Thanks for all the great ideas. I guess I will start going down the list one by one (startin with the cheapest of course) to try to get her purring again. And yes, I put in NGK platinum plugs (which is what I've always used). I'll post again if I have any more questions or if I can get her fixed. Thanks again Quote Link to comment Share on other sites More sharing options...
Scooby96 Posted March 7, 2009 Author Share Posted March 7, 2009 It seems that it was the coolant temp sensor. Just changed it a couple of days ago ( I have been really busy and couldn't get around to it til now) and it has been running great. THANKS NIPPER. Also changed the plugs (AGAIN) and even though they were new (about 1 month) the rich running must have fouled them, they smelled like they had been soaking in gasoline for a couple weeks (I guess they have been). Also changed a few of the hoses running from the PCV which I realized were almost blocked by oil gunk when I was trying to get to the colant temp sensor. Thanks to all of those that helped me out and Scuby thanks you too. Quote Link to comment Share on other sites More sharing options...
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