Hi, I have a manual 07 Subaru Impreza 2.5i. I’ve had it for a few weeks now and absolutely love it. But I’ve come across a problem that i don’t know witch way to go with. Both cylinders 1 and 2 misfire and all the lights in my car flicker like the alternator is going. Just want some opinions on if these problems are tied together in any way or if I should just replace the alternator and coilpack. Btw I did change all 4 spark plugs and the car ran way better so I kept pushing it untill I got the misfires again.
Sounds like 2 problems. First, is the check engine light on? If it is, what are the codes, in the form of P1234.
Your misfire might be a failing head gasket if cylinders 1 and 2 are side by side. A compression check should confirm that if both 1 and 2 are low. Leaking across the gasket from cylinder to cylinder.
You need a voltmeter to diagnose a failing alternator. It should produce 13.6 to 14.6 volts while the engine is running. I’d also look for corroded grounds.
The codes are P0301 and P0302. On the gasket side of things. I’m not sure about that. Since it’s a boxer I’m 90% sure 1 and 2 are across from each other instead of next to each other, but I could be wrong I’m not to mechanically inclined. I’ll try to check the alternator with a voltmeter thank you
“Witch”? Yeah it’s close to Halloween. You can get a plug in voltage and battery tester for $10-15. If the voltage is fluctuating then likely an alternator issue or connections as mentioned. Really need to plug the volt meter in though to see what it is doing. Who knows on the misfires? Could be electrical such as the coils/wires or mechanical. If the coils are cheap, you could do that but otherwise really need to pay $100 for a diagnosis.
First things first. Make sure the battery and charging system is in working order before any other diagnosis or repairs are made. Clean both ends of both battery cables, check voltage from alternator, should read 14 volts or higher with engine running. Fully charge the battery, then bring the car to a parts store for a free battery test. When all this is done, if you still have misfires, then it is time to deal with that.