91STT Thank you for asking. It is very kind of you. At first, I thought that you could read my mind about changing O2 sensor. I actually told you.
About O2 sensor:
Couple months ago, I started to notice that my rpm was not stable (swing by +-300 rpm) at idle or D without moving. The service engine soon was on last week. I went to advance, the guy told me it is A/F ration problem. I didn't see the exact code. I went to the dealer right after and force them to scan my car for free. The dealer just put a new fuel pump (and fuel switch) in Feb 2010 (under warranty) and I blamed the problem on their work. The result from the reader was [A/F sensor1 (B1), P1278]. The sale person at the dealer knew that I would not do the work with them. The car was parked outside when he gave me the scan result. I asked him for the price anyway. He told me $220 for the O2 sensor and $140 for the labor. I shopped around and bought the sensor from advance for $98. It looks like the sensor is on the engine header. I will have to fine the wrench that will fit in the area or remove the metal sheet that cover the header. I will have to double check the location of the sensor again before (if) I do the work.
I would appreciate your suggestion about this. I can always return the sensor if I don't need one.
About the shift interlock:
My car did not make that noise before. Right now, the shift interlock makes pretty loud noise. It sounds like you tap a pen on a table. I did not recall that I heard the noise when I test drove my car after the brake job. I went to goodyear after to let them flush power steering fluid and clean the fuel injectors (to make sure the inside parts are cleaned bofore I install a new O2 sensor). I started to hear the tap noise when I drove my car on that night.
I look through under my hood and saw some hand print here and there. The battery terminals were cleaned by water but there were not disconnected. Would it be possible that I have some loose connections that can couse the shift interlock noise? (The mechanics might have knock some switches off.)
How do I make the noise go away? Many people told me that it is ok to have some noise from the interlock, but it is loud and I am worried. I have a repair manaul from nissan. I saw that the swicth is located on the driver side under the shifet lever. How hard to get in there and how can I fix the problem? Can I just adjust the adjuster on the interlock system? If it is 100% safe to have the noise, I can live with that. I do not want to touch any thing that is close to transmissionm system.
I will be awaiting for your reply.
Thank you
DRT
FYI:
-Nissan sentra March 2005 (New) 60k
-Fuel tank recall (fixed October 2005, the gas mileage went down from 35 to 31 miles/gallon highway)
-December 2005, Replace rear drums (warranty)
-April 2008, Starting problem when the weather is hot (engine can be cool or hot). It cranked but would not start right way. I always got lucky after several times of trying. (never have to tow)
-In Feburary 2010, high pitch noise from fuel pump. Advance told me it is the fuel filter. Fuel pump has 5years/ 60k warranty so I went to the dealer and they replaced the fuel pump (warranty, the gas mileage came up from 31 to 34 miles/gallon highway). The pump also came with the fuel switch (or whatever name it is) and that fixed my starting problem (dealer told me). The switch was not under warraty but it came with the pump so it was free. (Lucky me!)