Johnnny

Hi i am having misfire in the Cylinder 2 on my Audi Q7 3.0T from 2017 with 146K Km i am having misfire in one single cylinder when i am hard accelerating i already swapped my ignition Coil from the Cyl 2 to the Cyl 1 and also change that exact spark plug on the dealer what i didnt understand why is only occuring in that single cylinder i also change my PCV Valve and hoses and also make a carbon cleanup and still having problems and the intake manifold when i took it to a repair shop when they changed the pcv valve they inserted the intakes manifold wrong and they were stuck so after sending the car to the dealership they adjusted it but still a error code Note(the car dont feel like the intake manifold is stuck after the adjustment). for the moment there is no Check engine light in my dashboard only when i hard accelerate it haves the misfire and car enter in limp mode it canīt even climb a hill.
the 5 spark plugs are Denso and the one changed in the dealership is the OEM one

And this is the image of the cyl 2 spark plug which it was change at 140K KM

Thanks in advance for any suggestion i could have

kelisko

Is your engine consuming excessive amounts of oil? What is the rate of your oil consumption?

Johnnny

I dont have an exact number but based on the distance i drive daily i would say each 3k or 2500k km each i refill oil

clars

I’ve had clogged injectors cause misfires on previous vehicles. Could try a fuel system cleaner and see if that helps.
Also once you start getting misfires the ECU sometimes tries to adjust to resolve it and can then make other weird errors occur.

Lorryist

I’d be looking at those intake manifold codes first.

Johnnny

Ok i will try injector cleaner
and for the intake manifolds the most probable thing is that during cleaning they might damage the sensor the dealership told me even if the error remains if the car dont feel slow i dont need to worry because it can only be the sensor and for the range/performence in bank 1 and 2 if i scan the car with the engine on when i rescan it again both code error de do not show up only they show up when the ignition is on also if the intake manifold close stuck appear even if it working it can make the car slower?

kelisko

This engine has the reputation of killing its piston rings and burning its exhaust valves. I had the hide cylinder code when I was around your mileage and it turned out that all cylinders' compression were below spec and one of them completely lost compression causing the misfire. Start with checking compression in your cylinders before replacing any part.

Johnnny

Alright il test that but before that i would like to know which is the correct compression of the cylinder also to know the procedure with the engine since this one dont work with key ignition

Lorryist

Does your OBD2 scanner have a compression test? Certainly not the most accurate, but it should show if #2 is lower than the rest.

Johnnny

Alright i am going to test