I have been having a misfire and power loss issue for a while. Changed maf to new OEM one earlier this past summer. Didn't help. Got worse later actually. This past Sunday I put a set of eBay coil packs in, new NGK platinum plugs and cleared codes. Now the car doesn't have an obvious misfire like before Or misfire code but..Still doesn't run right. Stumbles at idle and Bogs down sometimes when trying to accelerate. Ran codes and have a p0430 code. Could a bad cat or 02 been causing all my problems all along or misfiring caused a bad cat or 02?

 

sounds like a plugged cat. change it or gut it.

 

yeah what I was afraid of. I've wanted the cats gutted anyway for little more performance and peace of mind. just seems to be a major pain to get them off and to deal with cel light. guess i rather deal with that than to put stock cats back on it.
strangely today though the car has run really normal. good idle and pulls pretty good. bluetooth scan tool even stayed connected where before it kept disconnecting from my phone. strange. used app on my phone to adjust idle to 700rpm and it has stuck so far today. I did notice that the clamps on two of the large intake manifold hoses, rear of manifold was not clamped down in place. car was running good today before i corrected the hose clamps though.
P0430 code hasn't come back yet but had to be reason it came on the first time. car has 190,000+ on it so wouldn't be surprised about bad cat or 02 sensor by now.