Manifold/header/muffler/tail Pipe problems of the 2004 Nissan Sentra

I was driving my car home from work and my engine started to miss fire. About half way home on the pulaski bridge my car shut off. I was able to restart my car while it was in motion as I drive a stick shift car. I still noticed the car was still misfiring so before I drove threw the holland tunnel I pulled over and shut the car off. I gave it a few minutes and restarted my car and it didn't sound as bad so I continue on to manhattan. I got about three blocks from my home and car shut off again. This time it had a engine light. I parked my car went home and got my obd2 reader and found a code p0301 cylinder one misfire. I pulled the plug to find it was in closed position, so I looked up on the internet and found that this engine has butterfly screws in the intake manifold that come loose and causes this to happen. I took my car to Nissan and was charged to replace the spark plug. This did not fix the problem I myself am a mechanic so I removed the intake manifold to find I was missing a screw from the butterfly above cylinder 1. Nissan corporate was called and so far nothing has come out of this. I need help please.

In July of 2011 my 2004 Nissan Sentra se-r spec v had some issues. I had a check engine light come on and had light blue smoke come out of my exhaust while accelerating and had been starting to notice bad oil and fuel consumption. I took it to the Nissan dealership and they searched for any open recalls on my specific car based on running my VIN number into the database and they told me it was not one of the affected vehicles. After hooking up a code scanner to my car they found the following codes, p0420 (catalyst system efficiency below threshold), p0302(cylinder #2 misfire), p0303( cylinder #3 misfire) during the diagnosis they said that the pre-cat (exhaust manifold) had come apart and the material inside had glogged my exhaust system and gotten sucked back into my cylinders and scored the cylinder walls. They stated that they had also found valve damage and even found some of the cat material in my oil. Nissan was kind enough to replace my engine block and the pre-cat manifold as well as my secondary catalytic converter even though they said it was not a vehicle affected by the recall campaign that Nissan had issued. So here I am a little over 2 years later and guess what? it came back. I am having the exact same symtoms as before. I took my car back into the same Nissan dealership and they will not fix it again without charging me. They refused because it was never a part of the recalled vehicles and it is currently not under any warranty with its 105,000 miles. So, I ask them, why did they fix it the first time? their response was, and I quote, "it was a courtesy" to which I said, "hmmm, so you guys do a courtesy fix for over $3,000 worth of work for a car that supposedly "isn't" part of a recall campaign?" - they didnt have much to say after that other than my best bet is to take it up with the manufacturer and they refuse to help as well. This car is a trap.

The contact owns a 2004 Nissan Sentra. The contact stated that the vehicle would idle and lose power frequently while driving less than 75 mph. The vehicle was taken to an independent repair shop and they discovered metal pieces under spark plug number 1. The mechanic removed and replaced spark plug number 1; however, the failure persisted and has been to the dealer. On a separate occasion, the vehicle would stall. An independent mechanic removed the intake manifold and found even more metal pieces in the engine from the power valve. Two of the power valves were irregularly shaped and were broken off into the engine. The failure has not been remedied. The failure mileage was 69,000 and current mileage was 70,000. Updated 01/14/09. Updated 01/15/09.