Zephrant Posted January 4, 2016 Share Posted January 4, 2016 2006 LGT- Last summer I replaced all belts, hoses and the water pump. (Didn't think the timing belt had been done, but evidence says it probably was). Took it on a trip from Spokane to California and back over two weeks and it was fine. The day after we got back I got a CEL. Codes said P0171 (lean), and P0301, P0302, P0303, P0304 (missfire in every cyl). The car drove fine, so I figured bad gas, and ran some treatment and new gas though it. Cleared the codes, tried different gas, etc. Never got them to go away and stay away. Cleaned the MAS several times, checked the K&N air filter, looked for vacuum leaks, etc. Had the upstream O2 sensor go out on my Forester, so bought a new one for the LGT too. Changed it, and no impact of course. 147K on it, so I decided to put in new plugs. The ones coming out looked fine, put matching factory-stock ones in and now it is really bad. Miss-fires, CEL flashing at me, gutless, sometimes dies at idle, etc... Bought a new MAS from Amazon and just put it in tonight, no impact. Took it down the road to get gas, put in another bottle of injector cleaner / gass dryer, but I'm not thinking that is going to help. The Tee behind the Alt looks like it is OK- I've not pulled the Alt again to really check it. No visible cracks in the intake hoses, engine is very clean. I'm concerned that changing plugs made such a big difference. It took a minor CEL annoyance and made my care undriveable. I've read that the fuel filter is in the tank? Anyone have any suggestions on things to check that I've missed? Link to comment Share on other sites More sharing options...
whitrzac Posted January 4, 2016 Share Posted January 4, 2016 You probably have a vacuum leak. Check the T under the intercooler. Check the turbo inlet. Read the thread on vacuum leaks. Link to comment Share on other sites More sharing options...
Zephrant Posted January 9, 2016 Author Share Posted January 9, 2016 Yep, nailed it it one. I was reluctant to pull the TMIC since I've never had it off, but it was no trouble. Hose going towards the firewall was siting there loose. I'm wondering if I pulled it off when I was fighting with the coil on the driver's rear cyl. It was a bear. Still have a P0304 code- Going to pull the coil pack and swap it today, and maybe check the plug again. I'm betting I've got something wrong with it. Thanks for the help! Link to comment Share on other sites More sharing options...
Zephrant Posted January 9, 2016 Author Share Posted January 9, 2016 Well the second time it was much faster. I pulled the plug and it was fine, gapped at .029 like the rest. Put it back and swapped the coil packs. Took it out for a spin, and it still hesitates and throws a P0304. : ( It's not thrown a lean code since I fixed the hose (80 miles or so). Link to comment Share on other sites More sharing options...
Zephrant Posted January 10, 2016 Author Share Posted January 10, 2016 Swapped injectors, still giving a code P0304. I pulled the fuel pump fuse, and tried to start the car. After it didn't fire for 10s, I thought the fuel pressure must be down. Wrong! Ended up with a face full of gas. Link to comment Share on other sites More sharing options...
Zephrant Posted January 19, 2016 Author Share Posted January 19, 2016 Swapped plugs 4 and 2, and the problem moved to 2. So I bought another new plug and put it in, and everything appears to be fine now. So in the end, it was a disconnected vacuum hose under the TMIC, and then a bad plug. I may have dropped the plug before initial install, or sometime over the several years since I bought them, so I can't blame Subaru, but it certainly looks fine. Maybe I'll get out the ESD gun at work and see if it sparks as expected. Link to comment Share on other sites More sharing options...
xt2005bonbon Posted January 20, 2016 Share Posted January 20, 2016 You're lucky it is just 15$ plug and not a busted ringland which would be a $4-6k fix . Link to comment Share on other sites More sharing options...
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