bergs Posted October 2, 2017 Share Posted October 2, 2017 Trying to get some ideas on what I'm hearing....and yes, a mechanic has checked it out. A few details: All stock The performance is sluggish/ hesitation under hard accel Engine tapping noise seems to be only on decel Sounds fine when cold however I have not run it above 3k until it is warmed up No CEL Could one of the lifters be failing? This is clearly a tap not a knock. Link to comment Share on other sites More sharing options...
MilesA Posted October 2, 2017 Share Posted October 2, 2017 Might be a sticky valve or valves. Subaru makes a top end engine cleaner that is introduced into the manifold through a vacuum hose (as for the brake booster), called Subaru SA459. It would do no harm to try it and see if your issue improves. Curious if you can hear this noise when the car is stationary, if it is revved up and allowed to go back to idle? If so, you could put a vacuum gauge on it. That would give you a bit more insight into what's going on. If you have the FSM, there are instructions for doing this test and interpreting the vacuum gauge readings. Link to comment Share on other sites More sharing options...
jcaroth Posted October 2, 2017 Share Posted October 2, 2017 Could be your fuel line dampers going bad. Happened to me this summer. Luckily, each damper only costs around $30-$40 OEM (there are two: a feed and return line damper). I was getting an annoying tap/knocking sound at lower RPMs. You can use the screwdriver-to-ear trick to listen to your dampers and find out if they're making the noise. Link to comment Share on other sites More sharing options...
bergs Posted October 2, 2017 Author Share Posted October 2, 2017 It seems to occur only when warm and I have not tried to free rev the engine. My mechanic friend offered a time donation so he didn't go shoulder-deep in diagnosis. He basically said "run it". When I grab the parts for my 2005, I'll also be picking up a can of top end cleaner. I'm guessing it's going to be a similar process to Seafoam. Link to comment Share on other sites More sharing options...
MilesA Posted October 2, 2017 Share Posted October 2, 2017 ...When I grab the parts for my 2005, I'll also be picking up a can of top end cleaner. I'm guessing it's going to be a similar process to Seafoam.Pretty similar process, it comes in a aerosol can and is sprayed slowly into the vacuum port on the intake manifold normally used by the brake booster. It's approved by Subaru for their engines. Do you have BtSSM? It might give you a few clues about the issue if you were monitoring while driving around. Link to comment Share on other sites More sharing options...
bergs Posted October 2, 2017 Author Share Posted October 2, 2017 No BtSSM and not a whole lot of desire to give banking information to Google Play. If there's a way around that tiny detail then I'm all ears. It'd certainly be a nice tool to have. jcaroth - Thank you for the suggestion. I'll check the fuel dampers as well. Link to comment Share on other sites More sharing options...
MilesA Posted October 2, 2017 Share Posted October 2, 2017 No BtSSM and not a whole lot of desire to give banking information to Google Play. If there's a way around that tiny detail then I'm all ears. It'd certainly be a nice tool to have. You can set a payment method in Google Play to accept Paypal or Debit card. Not very different from other online purchases except, of course, dealing with Big Brother. Link to comment Share on other sites More sharing options...
bergs Posted October 4, 2017 Author Share Posted October 4, 2017 Picked up the top end cleaner yesterday but it wasn't available in a spray can. I'll do the top end cleaning on Friday, change the oil and see what happens. Link to comment Share on other sites More sharing options...
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