1996 Grand Marquis LS 4.6L 116K. Have a P0420 Cat Code. Problem I am having is Hard Starting When Warmed Up. Starts great Cold and Cool. Runs perfect. Have a code P0420, looks like bank 1 cats are bad, but will this cause hard starts when warm

Thanks Ken

 

well, could be a bad O2 sensor, you might also have a fuel pump going bad. Hard to say really. If the cat is bad, that could cause the o2 sensor to see something it dont like, causing it to be difficilt to start. If its fuel pump that would make it difficult to start when warm, as it is starving it for gas. Cheapest solution right now is the o2 sensor. Also pretty easy. After that i would replace the cat. Bank 1 is the passenger side cat(there is 1 per side, bank 1 is passenger side catalytic converter, bank 2 is drivers side)...