Power Loss between 3000 and 4000 rpm please help

[APOBEK]

I have this problem in my r53 JCW 2004 model:
with 3rd and 4th gear and maximum acceleration, full throttle have power loss between 3000 and 4000 rpm like 2 or 3 small cut offs
if anyone can help me I would appreciate
Thanks

[Acallahan]

check fuel injectors and also what quality of fuel are you running ? I would try a couple bottles of fuel system / injector cleaner in your tank and see if there is any improvement. I also would get the codes checked and see if you are throwing any codes.

[APOBEK]

The problem start after the inspection 2 service at 82000 km
they put wrong plugs BKR6EQUP NGKs fitted rather than the specified BKR7EQUP and start the cut offs
I go the next day and they put the correct plugs but the problem don't go.
the dealer check the fuel injectors and they are OK
I put yesterday a bottle of cleaner and I wait. make 60 km and see some improvement but the problem is there
Thanks

[APOBEK]

I check the coil for corrosion I clean them and put dielectric spray
The car is better
No cut offs in 3d and some times 1 cut off in 4th speed

[APOBEK]

I check the coil and the sparkplugs again I clean them with metal brush and put dielectric spray

THE PROBLEM SOLVED

Thank you all