Misfire on 2 cylinders

My Legacy GT wagon has been killing and running rough. When going from reverse to drive it often dies or from park to rev same thing. I scanned with cmputer said has a misfire on 2 and 4. Already changed plugs and fuel filter but no change. Timing is good, no vac leaks. Any suggestions?? maybe bad plug wires ??

Dealers are of no help unless you pay them and I refuse.

Do you have spark on those two cylinders ? is the coil good ?

1+3 and 2+4 are on the same bank. So if 2-4 are throwing codes. I would suspect the coil pack. Replace the coil pack.

Maybe something is up with your selector switch on the side of the trans since it does it when changing gears. A bad nuetral switch on the manual trans can cause this same issue putting it into limp mode causing 2 of the cylinders to miss fire. I cant remember if it was 1-2 or 3-4 though. The ecu usually does not throw a code for the misfire when this happens though.

check the timing.

 

the coil is split front and rear,

this means 1 + 2 fire together,

and 3 + 4 fire together.

so probably not the coil or the igniter.

 

cylinders 2 + 4 are on the same head, drive side.

if the timing belt jumped a tooth or two it could cause problems.

if the plugs and wires are not the issue, (most common cause of misfires)

then it may be timing.

 

remove the cam timing covers, 3 bolts each side,

and see if the timing marks match.

Ignition Control module could cause it as well

Check your valve lash

lol before checking valve lash please do a basic compression test before u get the valve covers off! !!!

 

but yes verify your timing mark lines up. get a spark plug tester or just ground the plug wire to a vehicle ground and rotate the balancer till the lines match up u should get a spark from cylinder 1 at the same time the marks lined up.

 

(comes from small block knowledge but if the firing order starts with one it will work.

 

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When running in park does it miss or does it just start when you change gears?

Compression test first. Something fishy.

i'm pretty sure the ECU adjusts the idle when you shift out of P or N to prevent stalling.

or to keep it running under greater load,

but i'm not sure exactly how or why.

 

but if the car stalls in P or N, then there is an issue,

like a vac leak, or a mis-fire on 2 cylinders, that lets it die.

these cars will run on 3 cylinders, and you can keep them running on 2 ,

but they may not idle on only 2 cylinders.

 

cure the mis-fire first.

check the timing .

I have changed the splugs, wires, coil pack and timing belt. The timing was off by about 1 inch(yikes). When put all back together the codes for misfire on 2 & 4 went away and showed no codes at all. It wouldnt stay running was rough with a very low idle. Im going to check the timing belt first to make sure its not off a notch before buying anything else. Thanks for all the input from all its very helpful

Here's a good tip. Once you get the t belt on and pull the pin on the tensioner rotate the crankshaft two times. Aligning the cranks timing mark then double check all of the marks. When I do the DOHC t belts I will offset the left banks cam gears clockwise about a tooth. This is because sometimes once you adjust the tensioner the right bank cam gears pull the t belt and will knock the left side off a tooth or so.

It wouldnt stay running was rough with a very low idle.

check the large vac hose, bigger than your thumb,

that runs from the IAC on the rear of the intake manifold, passenger side,

to the bottom of the plastic intake plenum.

it is easy to miss because you can not see where it connects to the plenum, it is on the very bottom side.

it is common for it to come lose any time you have the air filter box open or the plenum disconnected.

The knock sensor on these cars crack, usually they throw multiple missfire coedes. You can visually check if its cracked, and most likely thats all you need to replace.