kec789 Posted April 20, 2012 Share Posted April 20, 2012 Hello all! I have an 06 Legacy 2.5i (non turbo) with 113k on it. I had a pretty big maintenance done on it 6 months ago and of course discovered it needs a new head gasket. The price he quoted to do that was outrageous so I skipped that and had him do engine oil flush, service the transmission, change a couple of belts, Air filter, etc, etc. I'm giving you guys this info in case that head gasket can somehow be the cause to my new problem. Things have been running great for the past while except for the occasional check engine light with the famed P2040 code. From most of my reading I have found that code can be related to a cat getting too hot and going out. I used my tool to reset that light and ran some good fuel injection cleaner and started running higher octane gas. (In fact, that CEL hasn't been on for a while.) Skip to now. End of last week, and into this week I noticed that under hard acceleration the car is just struggling to go, like something is holding it back. It feels like it's starving for fuel or air, or something. If I'm going up a hill it's even worse and struggles even more. Same thing if I flip on the AC. Now, if I'm just tooling around town and driving normally you really don't notice much of anything being wrong. But if you punch it, it will down shift and try to get a move on but again it's struggling. I didn't have the spark plugs done when I last had it serviced so I ordered some higher-end NGK's and did that this evening. The plugs that came out REALLY needed to be replaced so I got excited thinking this might cure my problem. I'm thinking bad spark, bad ignition, bad performance. I took it right out and up my hill and immediately noticed that didn't fix my problem. With the rest of my research, and with the CEL I have gotten a handful of times, I'm thinking my catalytic converter is toast. If this is the case is there any way I can test this myself or do I need a shop to do this? I know I'm probably going to have to take it back in but I figure it wouldn't hurt to ask. If it ends up being a bad cat what should I expect to pay? Is this something I can get done for 3-500 bucks or am I looking at something a lot more than that? I have no problem getting an after market one to save some dough. Is there anything else you guys would check? I don't really have many tools to do anything drastic but if there is something reasonable coast-wise I'm willing to try. Thanks for the help everyone. I'm in SLC, Utah and don't have a "car guy" I trust in this city. The last place I took it in to to have those services done did do a good job but they are expensive and always list off a thousand things they "recommend" replacing. Quote Link to comment Share on other sites More sharing options...
ocei77 Posted April 20, 2012 Share Posted April 20, 2012 Put car on stands in front. Rev engine. Remove bolts that attach mid pipe to second cat. Start and rev again. If it revs freely now its the second cat. If still no, reattach and this time remove header from 1st cat and test again. This should be able to tell you if the cat is clogged. O. Quote Link to comment Share on other sites More sharing options...
ivans imports Posted April 20, 2012 Share Posted April 20, 2012 I had one i just did heads on that the front o2 was damaged from burning coolant try the front o2 but fix your headgasket first so you dont wreck new one thiss car did not set a code just ran like the exhaust was pluged no power and very lean Quote Link to comment Share on other sites More sharing options...
kec789 Posted April 20, 2012 Author Share Posted April 20, 2012 Thanks for the replies guys. I'm thinking if it WAS the cat having issues I would probably be seeing the CEL again, right? Ivan's: Could you snap a pic of where the front 02 sensor is? Or tell me where it is? Is that a tough thing to get to and replace? OCEI77: The engine seems to rev fine while just sitting there. Seems to only struggle when under load, as in punching it or when climbing a hill. It does "feel" like a clogged exhaust though... Quote Link to comment Share on other sites More sharing options...
davebugs Posted April 20, 2012 Share Posted April 20, 2012 That sounds like a knock sensor could be a possibility too. Usually they set a code - atleast for "pending". See if you can see if it's cracked. I've had good success for the P0420(catalyst below efficiency) with Subaru's, VW's, and recently a Toyota Rav4. Cheap and easy to try. Quote Link to comment Share on other sites More sharing options...
brus brother Posted April 21, 2012 Share Posted April 21, 2012 That sounds like a knock sensor could be a possibility too. Usually they set a code - atleast for "pending". See if you can see if it's cracked. I've had good success for the P0420(catalyst below efficiency) with Subaru's, VW's, and recently a Toyota Rav4. Cheap and easy to try. Was there a different code for knock sensor? P0420 code (at least on my 05) says nothing about knock sensor. It is an intermittent code as well. Would this be consistent with your findings? PS where is the knock sensor? Ivan Imports: I already replaced the bank 1 front O2 sensor and within minutes threw 0420 again. I thought this odd since the car was driven only 2 cycles... but then again it goes off (without my resetting) for a while before returning. Quote Link to comment Share on other sites More sharing options...
ivans imports Posted April 23, 2012 Share Posted April 23, 2012 the one i had set no codes just ran very lean and whould not go like a pluged feul fillter or low feul preshure the o2 senser must have been shorted lean but not failed enuff to set code the front sensor is under the ps cv axle iner end Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 23, 2012 Share Posted April 23, 2012 Knock sensor is P0325. And they can go bad and cause trouble without setting a code. Plenty of things can cause loss of power and a P0420 code. Air leaks in the exhaust, vacuum leaks, a bad oxygen sensor, a dirty MAF sensor, clogged air filter, misfiring. Any of these could cause an issue where the engine struggles for air or fuel and causes lack of power under load. Start with some simple stuff first. Not saying you should go tossing parts at it, but make sure a squirrel or mouse hasn't filled the air filter with acorns. Check under the hood for loose vacuum hoses, breather hoses, make sure the clamps on the intake tube are tight. There's not an easy way to check the fuel filter, but if it hasn't been replaced within the last year or so, that could be suspect as well. Quote Link to comment Share on other sites More sharing options...
jarl Posted June 28, 2012 Share Posted June 28, 2012 Just a couple months late Did you fix your problem? If "no" and you have access to a vacuum gauge (or buy one, those are cheap), go to: http://www.secondchancegarage.com/public/186.cfm Check the "Scenario 14" Quote Link to comment Share on other sites More sharing options...
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