cardana24 Posted July 10, 2006 Share Posted July 10, 2006 Hi, I am new to the forums. I am working on a 98 Legacy GT with the 2.5 L engine. I just scanned the codes from the car with my OBDII scanner. It returned two codes. First one was P0303, with is cylinder 3 misfire. Second was P0304 cylinder 4 misfire. Are misfires common in these cars? What usually causes them? I was thinking of starting off by cranking the car at night to see if I could see anything arching. The cars that I have all have coil packs, so when I have a misfire it is usually a coil pack going bad. Does anyone have experience with fixing misfires on these cars/engines? Thanks for any help. *Also* I was searcing on google, and someone was saying that there is a coil shared for every two cylinders...is this true in the 98 2.5's? When I look at pictures of the coil it all looks to be one peice. Also which cylinder is where? I see that the plugs are in the side of the engine as opposed to the top...I'm not familiar the the boxer engines. Link to comment Share on other sites More sharing options...
mickeyd2005 Posted July 10, 2006 Share Posted July 10, 2006 Misfires could be caused by many different things. Here is my experience. I had a '98 Outback Limited. I think the engine is identical to the '98 Legacy GT. I also had the P0304 code after about 100000 miles. If I erased it, it would come back after a month or two. I never felt the misfire. Eventually, I changed the air filter (it was clogged), spark plugs (OE plugs were down to nubs), and I ran Chevron techroline through the fuel system. I still got one more misfire after I changed the air filter and plugs. I think that was because the ECU was adjusting to the drastic changes. After that, the misfires went away. You may want to change the fuel filter too. Link to comment Share on other sites More sharing options...
cardana24 Posted July 10, 2006 Author Share Posted July 10, 2006 thanks for the advice. What's happening with this car is more severe. When you come to a light or even when you are driving it will cut off randomly. The misfires can be felt and the car is cutting off. Link to comment Share on other sites More sharing options...
KegTapper Posted July 10, 2006 Share Posted July 10, 2006 Must be a bad day for those codes, I got 'em too Link to comment Share on other sites More sharing options...
Opie Posted July 10, 2006 Share Posted July 10, 2006 Misfires are usually pretty easy to run down... 1. Are the plugs more than 60k old? If so replace. 2. Are the plugs made by Bosch or Autolite? If so replace with NGK. 3. How is the resistance on the plug wires? If out of spec, replace. 4. Pull the plug wires out from the coil and inspect the leads on the wires and in the coil, Any corrosion? If yes on wires replace wire set, If yes on coil, replace coil. 5. Check the timing, is the motor in time? If not reset timing, replace timing belt if necessary. Check tensioners and pulleys at the same time as they can make the T-Belt jump time if the are not working correctly. If the above doesn't solve the problem you will need to check each injector and for carbon build up on things like the idle air controller, etc. Link to comment Share on other sites More sharing options...
SLegacy99 Posted July 10, 2006 Share Posted July 10, 2006 I had a misfire, wrong brand of spark plugs. Platinum NGK's only please. Link to comment Share on other sites More sharing options...
cardana24 Posted July 17, 2006 Author Share Posted July 17, 2006 The plugs have been replaced (need to find out what brand was used). Not much has changed other than the car does not die when the AC is on. I am assuming something with the faster idle is keeping the car running. Also when you say to check the timing, I was under the impression this was a distributorless system...therefore its controled by the computer. I don't think the timing belt has been changed recently so the car should not be out of time unless the belt jumped. Link to comment Share on other sites More sharing options...
Opie Posted July 17, 2006 Share Posted July 17, 2006 Also when you say to check the timing, I was under the impression this was a distributorless system...therefore its controled by the computer. I don't think the timing belt has been changed recently so the car should not be out of time unless the belt jumped. Exactly, as the tensioners and such get old they can drag and cause the belt to jump. Link to comment Share on other sites More sharing options...
kkushner4474 Posted July 17, 2006 Share Posted July 17, 2006 have the same exact problem with 3 and 4 misfire. I got rid of 4 and have only 3 left. I did sprak plugs, spark plug wires and serviced the coil pack and even did some fuel injector cleaner whcih seemed to help alot. I would start of with the cleaner. Still have the misfire in 3 and dont know why. SUBARU LEGACY INTERNATIONAL CLUB :: View topic - My never ending problem http://legacygt.com/forums/older-legacy-performance/37352-help.html my threads good luck Link to comment Share on other sites More sharing options...
cardana24 Posted July 17, 2006 Author Share Posted July 17, 2006 have the same exact problem with 3 and 4 misfire. I got rid of 4 and have only 3 left. I did sprak plugs, spark plug wires and serviced the coil pack and even did some fuel injector cleaner whcih seemed to help alot. I would start of with the cleaner. Still have the misfire in 3 and dont know why. SUBARU LEGACY INTERNATIONAL CLUB :: View topic - My never ending problem http://legacygt.com/forums/older-legacy-performance/37352-help.html my threads good luck Did you ever change your coil pack? I see you said you serviced it. Link to comment Share on other sites More sharing options...
kkushner4474 Posted July 17, 2006 Share Posted July 17, 2006 no but i checked it ou with the rsrtiance and how much ohms and what not it was putting out and letting circulate through it and it all checked out fine. And mine only misfires at 70 mphs 3000 rpms and 5th gear. Im leaning towards a faulty fuel injector Link to comment Share on other sites More sharing options...
cardana24 Posted July 17, 2006 Author Share Posted July 17, 2006 I just talked to the owner of the car and she said that it is running worse, since the new plugs...she was not sure what plugs were put in but she is going to check tonight. I am going to re-set her codes tomorrow with my scanner, and then we will replace the coil, and add some fuel injector cleaner. Also what grade fuel do these engines call for? Link to comment Share on other sites More sharing options...
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