Very confused about what the problem is here.
the car drives ok when driven gently but when you floor it, it looses all the power at 3500- 4000rpm is backfiring and it doesnt acelarate more.

I had a bad cat and was hoping this was the issue. I have replaced all the filters , spark plugs and cleaned the MAF with CRC's special product.

After all these , the problem was still there and decided to bite the bullet and go for the OEM cat. As i was driving to my indy the CEL came on.
I had 3 cylinders missfire and random missfire code. I was hoping that the clogged rattling catalytic converter was causing all this.

I had the cat installed yesterday and a O2 sensor as well. Took it for a drive and the problem is still there . The CEL came back on with the same codes exept one cylinder.First time was 2,4,8 and this time is 1,2,4.

I am very confused and have allready paid big bucks without any improvement at all. I ll have my indy change coils positions

Any help is appriciated..