Random cyl 4 misfire Subie style on interstate

[DSM Chase]

Car drives great I drive it everyday an hour, anyways twice this week this has happened already. Car is making power as it should killin beamers down the interstate and then boom I'm running on 3 cyl, sounds like a Subaru and no power. But as soon as I turn the key off and back on it stops? First time it did it, ecu threw a light "cyl 4 misfire" had it cleared comes back within a few miles. Don't have link on this car yet either.

Any ideas

 

[boost97gst]

Check power transistor, coil pack, wires, and IF it goes lean when this happens check your ecu to injector wiring and the wiring through the resistor box. This is critical. Read your plugs as well. See if one is noticeably darker or leaner than the rest.
This is a tricky problem that i struggled with for a year. Only at idle for me. Changed out the coil pack and it fixed it. I think . It may have beent he inj wiring also. I fiddled with everything when i was troubleshooting it, opened a thread and all.
Good luck

 

[DSM Chase]

Plugs are new wires are new, it's something freaking the ecu out. Because as soon as I turn the key off and restart the car, It stops.

 

[born2race]

When my injector went out it sounds similar to you, it would happens randomly then after a few minutes it would stop. Until one day on the highway it crapped out all together, I swear sounded exactly like a subie. May wanna make sure ## injectors are working properly, maybe switch them around see if the cylinder misfire changes

 

[DSM Chase]

If it were an injector wouldn't it do it all the time? The car runs great and pulls, but then it will just randomly start running on 3 cyl, immediately if I shut the car off and crank it back up it stops. That wouldn't fix an injector if it were bad.

 

[Xploitn]

Born has a great idea. Try it so that you can be 100% sure it's not the injectors without spending any money.

 

[boost97gst]

Like I said, I had the exact same problem. Cycle the switch and it would fix itself. Check cas as well as what I listed above. Forgot to mention that

 

[born2race]

If it were an injector wouldn't it do it all the time? The car runs great and pulls, but then it will just randomly start running on 3 cyl, immediately if I shut the car off and crank it back up it stops. That wouldn't fix an injector if it were bad.

That's exactly what I thought, but you know how Dsms can be. I'm not saying I'm right, just that worked for me. Boost also has some great points, my coil pack went on me aswell which also killed one cylinders power.