Not sure of anything at this point. With the intake manifold off I should be able to see the valve stems.

[emoji1696][emoji1696]
Here's hoping!!

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Sounds like you need to fully remove the intake manifold at a minimum. At that point, things may become more clear.

A leakdown test should pinpoint where the problems are. Definitely figure out exactly what caused this before repairing if you want to make sure you don't re-do it all later.

Sounds like a major problem since you had both intake and exhaust damage. Complete guessing at this point, but maybe a stuck injector filled the cylinder, hydrolock cracked the head, and boom, exploding into both intake and exhaust.

A local shop pulled my intake manifold and replaced it with the one I pulled out of another X5. Note that the manifold I pulled included all the fuel injectors. During the replacement process they noticed that the crank case ventilation valve was clogged. So they cleaned it out. The car started fine and now runs great. It turns out there wasn't any exhaust problems, all the noise was coming from the intake. So the question is, can a clogged ventilation valve cause the backfire or was the problem fixed by replacing all the fuel injectors? I have the original manifold and I'm going to check out the injectors.

I would have a compression test done on the engine and if you have a cylinder(s) with low compression I would have a cylinder leak down test perform on that cylinder(s).

Thanks upallnight, I'll do a compression test tomorrow.

I would also do a fuel pressure check both running and after shutting it off.