Hey guys I bought a 2004 Lincoln LS V6 with 90,000 miles recently. I traded my 2000 Toyota Celica and $1,600 for it. I thought it was a pretty good deal. My Celica had 142,000 miles, the exterior and interior was in really rough shape, and it had multiple cylinders with misfires. I valued the Celica at about $1,000 so in my eyes I paid $2,600 for the LS. Before I explain, I want to say that I have done a lot of research on google, youtube, and this forum prior to posting this thread. At first glance the car seemed really nice but I quickly noticed it had a bunch of problems. There was a major roof leak that caused water damage to the interior of the car. I fixed the roof leak pretty quickly with silicone. For the most part there aren't any major stains in the interior. There is really bad water damage (stain) on the driverside speaker, door, and steering wheel which I'm hoping I can very carefully paint over. The storage part of the trunk (under the base where the donut lies) is all rusted from water damage, so I also plan on painting that over. But the water damage is the least of my worries. The service engine light popped up after a few days of driving. I got a P0430 code which is "Catalyst system efficiency below threshold bank 2". I did some research and put some CAT Cleaner in the tank. Nothing happened. Next I decided to change the oxygen sensors. The car itself drives very smooth and the engine doesn't make any noise so I assumed that the catalytic converter was in good shape. After I changed the sensors, I reset the service engine light and unfortunately, it popped back up. Now I'm thinking the catalytic converter is going bad. Anyone have any advice? I would hate to replace the catalytic converter because I feel like its going to cost $500-$1000. Luckily, I don't have to do it IMMEDIATELY because the inspection is good till February. Another big problem is the A/C. The A/C does not work at all and blows BURNING hot air. I took it to my mechanic and he replaced a blown fuse and purged/recharged the system with refrigerant but it still did not work. He said that when he tried to turn the A/C on the compressor was not kicking on and he thinks it might be an electrical problem. He told me to bring it to a Lincoln dealer. I did the diagnostic test and got the codes 27 98 and 12 65 pop up. I did some research and found a lot of posts about the DCCV valve. I Read these two threads which were helpful: Hot air comes from A/C, how to locate the the faulty parts? DCCV Fuse. Check it! From what I read the 12 65 is a dummy code that doesn't have anything to do with this model. The 27 98 is the DCCV circuit short to ground which means the valve could be bad or the wiring could be bad. I am tempted to buy the valve and replace, but I'd hate to spend the money and it not solve the problem. Is there anything I can do before replacing the valve? I am not opposed to buying a volt meter and checking resistance, voltage, and continuity. I just need to get walked through it because I have no background in electrical stuff. Also, my ABS and traction control randomly turns on while I'm driving which makes me think there is an electrical problem.