Flatfour02 Posted May 31, 2018 Share Posted May 31, 2018 Hi all. So my 05 Outback XT is getting a P0171 code. It's been getting it for a while, but before, when I would reset it, it wouldn't come back right away. Sometimes it would take a few months before it came back. Well now it comes back after only a handful of miles. So the car has near brand new plugs and packs. Brand new denso MAF sensor, the O2 sensor is only about a year old, and I'm not finding any vacuum leaks. In case you're wondering, the MAF and O2 sensors were replaced in hopes of solving this problem. So it's idling a little rough, and my gas mileage is pretty bad. It seems to drive okay once it's warm, but when you first start the car and go to drive away, it hesitates. After that it never does in again. Any advice? So far it seems the only thing I can actually check is for vacuum/exhaust leaks, but anything else is just swapping out parts. Any help is really appreciated. Link to comment Share on other sites More sharing options...
grovlet Posted May 31, 2018 Share Posted May 31, 2018 Check the condition of the Coil Pack connectors - they tend to get a little dry and then crack - then the connection becomes loose.... A while back one of mine actually crumbled apart and broke - happened to come fully loose from vibration while driving down the road - and the car started to run horribly - 3 Cylinders - LOL.... Pretty quick fix is to just zip ties them in place if the locking tabs break as well. Link to comment Share on other sites More sharing options...
relative4 Posted May 31, 2018 Share Posted May 31, 2018 Do you have BtSsm or RomRaider? A very helpful starting place is to post your learned values. How did you test for vacuum leaks? Have you checked the grounds? Link to comment Share on other sites More sharing options...
Flatfour02 Posted May 31, 2018 Author Share Posted May 31, 2018 Do you have BtSsm or RomRaider? A very helpful starting place is to post your learned values. How did you test for vacuum leaks? Have you checked the grounds? I did check the grounds. I only found two, one underneath on the driver's side head and one underneath the tmic. Should there be more? I do have an Accessport v2. For the vac leaks I just looked around and sprayed some brake cleaner on the connections and listened for rpm change. I did also check the coil pack connectors. They seem to be where they should be. Link to comment Share on other sites More sharing options...
relative4 Posted May 31, 2018 Share Posted May 31, 2018 There should also be one on the passenger head. If you're missing that one entirely, there's a good chance the driver-side one is in bad shape. Poor grounding can cause lots of problems like this, so that's a definite first step. Spray testing is not very effective; you really need to smoke test. You can get a paint can smoke tester on eBay for $65. On the AP, can you log the following: A/F Learning 1A...1D Roughness 1-4 Link to comment Share on other sites More sharing options...
Flatfour02 Posted June 4, 2018 Author Share Posted June 4, 2018 Well I found a vacuum leak. One of the connections underneath the intake manifold was loose. Couldn't tell by looking at it but you could see it when you pulled on it. That took care of it. I'm going to go ahead and hook up a ground on the passenger side head because there definitely isn't one. The one on the drivers side looks fine, but it also looks like it isn't oem. Somebody just took some 10gauge and threw it on there. Thanks everyone for your replies. I wouldn't have asked, but I had already looked for leaks, so I figured it was something else going on. Link to comment Share on other sites More sharing options...
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