I'm using diagnostic software INPA and ISTA/d to look at the numbers while the engine is running and couldn't in the TIS, the specifications for different engine measurements that a normal engine should have.

I'm looking for a spec sheet that says this amount of fuel pressure is normal, this amount of compression is normal kind of like how you get a blood test done and they give you reference values.

Back story:
I own a 2007 550i N62tu with 107k miles and after changing the valve cover gaskets, ended up with what I'm pretty sure was an intake backfire. Loud plasticity pops that quite honestly I was afraid to even start the car. I double checked the wiring to ignition coils. Threw cam shaft position sensor error so I changed all 4. Two exhaust and two intake. Then I got new spark plugs. Problem was still there. Tried to do a reset of adaptations and the valvetronic reset. I checked vacuum hoses visually and nothing seemed out of order.

I was a bit ignorant and didn't really look further into the problem and research other things. I didn't run a smoke or compression test at the time. I didn't check fuel pressure.

So I gave up and took it to the stealers. The backfiring it turns out was a bad ignition coil and it solved the problem. Didn't know how I could check which coil was bad, I know you can check the resistance etc but seemed beyond my capabilities at the time. However now there is intermittent misfires and they had to send it to another shop and the guy says it's a timing issue and it's charging me $1200 to fix.

But I'm curious how my timing went bad when I changed the vcg I didn't touch anything related to it. I would think maybe a bad fuel injector, fuel pump, valvetronic motor or solenoid could be at fault.

I just wanted to have a spec sheet so next time I can see what's going wrong with live data and isolate the problem better.

Thanks guys really appreciate any help