[Haywood]

Of course this happens when I'm 3 hours from my house and there's snowstorms all over the place!

Went to visit my daughter at school. Get in the car, start it up and the engine malfunction light comes on. Reduced power. RPM's limited to 4k. The car is rumbling and it noticeable louder. There isn't a BMW near where I am, so I find an AAMCO just so they can take a look at it. If you see a list of my mods, I installed the straight pipes myself some 4 months with no issues. So, originally I thought they came loose and it was losing back pressure. I also installed the intake and again haven't had any issues.

After they inspected the x-pipe and exhaust, they found no leaks and no issues with the clamps. (I went under the lift to look as well). The guy then ran a scan with an ODB tool and it came up as cyl 5,6,7,8 were all misfiring. Here are the codes if anyone can make sense of them.

P0300 Random/Multiple Cylinder Misfire Detected
P0305 Cylinder 5 Misfire Detected
P0306 Cylinder 6 Misfire Detected
P0307 Cylinder 7 Misfire Detected
P0308 Cylinder 8 Misfire Detected

It was too late to get to a dealership, so I got a hotel. Ironically, as I was driving to the hotel, the issue went away! I didn't chance driving home so I will stop on the dealership tomorrow to have them check it out.

Does anyone have an idea why this happened and then why it just went away?

Thanks in advance.