Replace coil pack on subaru legacy

SOURCE: Subaru Forester P0303, Cylinder 3 misfire problem

Having the same problem with my 2000 Legacy Outback. A mechanic friend of me said there is a limited number of things this could be (in order of likelyhood): plugs, plugwires, coil, fuel injector, bad compression/valve. He said he has 2 Subarus in his shop with a rough idle and bad gas mileage and both needed new coil packs. The coil packs in Subarus has 2 coils, one for the 1 and 3 and one for the 2 and 4. Each one of those coils has two coil wraps in each. These are wear parts and eventually they wear out. He said in Subaru they usually last 90,000-150,000 miles. So all things considered, he said it is 99 times out of 100 the coil pack. I would shop it around they seem to vary in price wildly from store to store. I found one for my car for $126 while another store had it for $200.

SOURCE: My 2002 forester started misfiring

Hello first of all

I would be glad to give you the best advice as a mechanic for 8 years 3 for bmw and 5 with ford motor company.

That being said your diagnosis is good and you followed the correct troubleshooting guide lines so good job with that. I am not super familiar with subaru but if you have one coil for all cylinders this is most likely not your problem but a good way to check your coil is take the spark plug out of head , then reconnect to spark plug wire lay spark plug near a metal surface and have someone try to start the car look at the color of spark if its blue spark your coil is not the issue if orange spark coil is faulty not firing a hot enough spark to fully ignite gas vapor. '

So with all that some newer cars do have coils with a coil pick up built in this may be faulty to if applicable to your car if so the only way to know is for you to change the coil.

However if the coil does not fix your issue i would strongly lean on a crankshaft position sensor and or a camshaft position sensor as they tell the ecu when to fire spark and in what order to fire it and are more commonly known to be faulty before all else.

The crankshaft position sensor is located either under the harmonic balancer pulley or facing the pully were the belt is not if under pulley you will need to rent from autozone a harmonic balancer pully puller its free just pay and get money back when you return.

camshaft position sensor is normally located were the distributor was located easy to locate if diffident though.


If your coil does not resolve the issue one of these two will.

Please if it helps 4 thumbs and testomnial would be greatful for thanks any ? just ask

SOURCE: 91 LEGACY STARTED RUNNING ROUGH

The cylinders are numbered as on the spark pack you changed. You might have done better putting the seafoam in the tank as an injector cleaner. Not sure why you changed so many parts, you seem to know how to get the codes from test connector lead hookup and the blink pattern. You might also want to check the fuel rail pressure and the crank and cam angle sensors. Before replacing the injector, swap the #4 injector with the adjacent one and see it the code moves with the injector or stays put. If the code stays on #4, then check the injector wiring, if it moves clean or replace the injector.

gord storey

• 477 Answers
• Posted on May 13, 2009

SOURCE: I have a 1997 Subaru Legacy Outback AWD. The

when you replaced the plugs , was one of them (cylinder 1 ) dirty and fouled ?
I'm thinking that bad rings in cylinder would give you low compression , and eventualy cause the missfire by fouling up the plug.
There is an inexpensive product that will help with the compression by filling up scratches in the cylinder walls. It is called Restore , and it is one of the only products of its type that I have used , and feel actually works.
Unfortunately , if your rings are broken , or badly worn , nothing in a bottle will fix them.

If your car had a distributor cap and rotor , I would change them too.

SOURCE: Coil pack only firing on front two cylinders on my

Did you try an ignition module?This could be your problem.Make sure you have good compression.