Muffinator Posted November 22, 2014 Share Posted November 22, 2014 After about 15-20 minutes of driving my Subaru, it loses power and sounds terrible, like it's running rough. I have been chasing this problem for awhile now and I have no idea what it could be. The car runs fine and sounds normal when I start it cold and continues to run fine even after it starts to get warm. No CEL, no pending codes. 150k miles. Any suggestions? Here's a list of what I have done so far: Head gaskets Timing belt, tensioner and pulleys Cleaned MAF, IAC, EGR and throttle body Replaced fuel filter and air filter. Replaced spark plugs and spark plug wires. Coil pack also replaced. I am thinking of changing all the vacuum lines and possibly even the fuel injectors, but would these cause a problem only after the car has been running hot for a while? Could a bad PCV cause an issue? Please help, this is driving me crazy! Link to comment Share on other sites More sharing options...
Muffinator Posted November 24, 2014 Author Share Posted November 24, 2014 Nobody?? Link to comment Share on other sites More sharing options...
johnegg Posted November 24, 2014 Share Posted November 24, 2014 is the timing correct? no codes? sounds a little like it could be something heating up and then being wonky, like a cam or crank sensor. or even the fuel pump. do you have good fuel pressure. Link to comment Share on other sites More sharing options...
Muffinator Posted November 24, 2014 Author Share Posted November 24, 2014 is the timing correct? no codes? sounds a little like it could be something heating up and then being wonky, like a cam or crank sensor. or even the fuel pump. do you have good fuel pressure. I'll get back to you on the fuel pressure but I do believe the timing is correct. I wouldn't think the timing would cause an issue only after the car heats up. The mechanic I go to for major repairs has a very good reputation and he can't figure it out. I am assuming he checked fuel pressure but I will ask him. No codes at all, nothing. Are cam and crank sensors do it yourselfers or does the whole engine have to come apart for those? Link to comment Share on other sites More sharing options...
propanejoe Posted November 25, 2014 Share Posted November 25, 2014 the wife's 02 forester had an issue with losing power intermittantly after being at highway speeds for about 25-30 miles. but would run fine at city speeds all day long. Went through a butt-load of oil too. swapped out the pcv valve and all is good so far. When idling no oil smoke or smell was detected and at highway speeds no one had their nose back there to smell and again nothing was seen but the tail pipe was sooty inside. Link to comment Share on other sites More sharing options...
Muffinator Posted November 25, 2014 Author Share Posted November 25, 2014 I can still hear it running rough in park. It almost sounds like the timing is off. Is this possible? How can I check this? Update: Removed the left and right timing belt inspection covers and inspected cam timing and all the marks line up. Upon doing this, I noticed that a 1/2" sized rubber hose coming off of the left head was not hooked up to the air box like the right one is. Reconnected it. Will have to drive the car later today for awhile to see if there is a change, but I am wondering if that could have been the problem all along. Link to comment Share on other sites More sharing options...
Muffinator Posted November 26, 2014 Author Share Posted November 26, 2014 Drove it for awhile. Although running a little better with the new PCV valve and the hose reconnected, it still has its moments. Maybe it's time to change all four injectors and a new MAF? Could a bad MAF sensor NOT throw a code? Link to comment Share on other sites More sharing options...
monkeyposeur Posted November 27, 2014 Share Posted November 27, 2014 Test the resistance across the pins of the injectors before you replace them. A bad MAF has never triggered a code in my experience. Cleaning them hasn't really helped me when I had a bad MAF either. I am also sick of using junkyard MAFs as well. So I just shelled out the $130 for a new one. Hard to say if that will fix your issue and it sucks throwing parts at the car hoping it works. A new MAF made my car run a lot better so it was worth it. Link to comment Share on other sites More sharing options...
Muffinator Posted November 30, 2014 Author Share Posted November 30, 2014 Test the resistance across the pins of the injectors before you replace them. A bad MAF has never triggered a code in my experience. Cleaning them hasn't really helped me when I had a bad MAF either. I am also sick of using junkyard MAFs as well. So I just shelled out the $130 for a new one. Hard to say if that will fix your issue and it sucks throwing parts at the car hoping it works. A new MAF made my car run a lot better so it was worth it. What would the resistance readings be on a good working injector? Link to comment Share on other sites More sharing options...
monkeyposeur Posted December 1, 2014 Share Posted December 1, 2014 They should be 11-12 ohms. I posted the FSM procedure in this thread: http://legacygt.com/forums/showthread.php/new-member-former-lurker-looking-help-198824.html Link to comment Share on other sites More sharing options...
buisman11 Posted December 7, 2014 Share Posted December 7, 2014 sounds like a crank pos. sensor. Link to comment Share on other sites More sharing options...
lancerswimmer89 Posted December 9, 2014 Share Posted December 9, 2014 do yourself a favor, and replace ALL of the clamps on the vacuum lines. I did a lot of maintenance, and made sure to put all the factory clamps on, and had the same problems you're describing. Once I started replacing the factory clamps with new worm clamps, i realized how worn the old ones were. After the new clamps were on, it ran like a top and haven't had an issue since! Link to comment Share on other sites More sharing options...
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