I Installed the Monster Motor Werks Header on my car and have a cel thrown. The first time I installed the header I had no problems but when I took it off to send it to Jet-Hot and put it back on there was a cel light. I went to autozone to check it out and here are the codes It came up with the OBII thing.

P0031 (oxygen sensor 1, in bank 1, low voltage)
P0300 (PCM determined that multiple random misfires have occurred)
P0301 (PCM determined that multiple random misfires have occurred in Cylinder #1)
P0303 (PCM determined that multiple random misfires have occurred in Cylinder #3)
P0304 (PCM determined that multiple random misfires have occurred in Cylinder #4)

I disconnected the battery but comes back on.
I think the misfires are stored codes or something and maybe I messed up the upper O2 sensor. But does this mean I need a new one or is it something else. Where can I get a oem sensor or better?
Is this one good enough?
http://cgi.ebay.com/ebaymotors/Oxyge...spagenameZWD1V

 

Go with oem, you can get it from the dealer. You probably effed up an 02 which is causing it to run lean or rich, thus causing the misfires. Replace 02 sensor 1 and that should solve your problems, you also need an antifouler for your header's 02 sensor which I would buy before going with a new sensor. They can be found cheap on ebay. Good luck.

 

so I also need an antifouler on the upper sensor? The bottom one has the mmw angled piece.

 

AFIK, but someone else help me out here...

 

You only need the anti-fouler on the s-pipe, not the header.

 

don't monster mw header comes with their anti fouler for free?

 

www.autotube.net has the antifouler for like $10.

 

look at the first code
its telling you the O2 sensor is broken

time to order one from the dealer

 

well thanks guys, i guess ill get the new O2 sensor 4 wire one and try that.

 

how much does that O2 cost?

 

i have the mmw headers and s-pipe......if i have a high voltage code for sensor #2...but it only comes on once a month, and only in the winter in the cold, and only when im going at least 70 mph....the sensor's just acting up, its not actually broken is it??

 

Might be... If it is acting up, that leads to it failing...

 

damn...anyone else got an opinion before i throw in the towel?

 

Ok I got an OBD2 code reader now.
I also installed the new O2 sensor. Here are the new codes thrown... Please help me

P103 Mass or volume air flow circuit high input (this one is new to me)
P2239 O2 sensor positive current control circuit high bank 1 sensor 1
P2252 O2 sensor positive current control circuit low bank 1 sensor 1

I followed the directions on the new O2 sensor but dont know if maybe i got the 2 black wires mixed up or something, theres no way to tell.

 

P103 is your MAF on the intake I believe. Donno jack about the other problems.

 

Yea I think thats what it is but does anyone know what might be my problem?

 

ive had that one....your maf is gone dude....i dono what you did but for mine, i accidentally nicked my injen cai with the wrench i was using to disconnect the positive battery cable. my car immediately went into limp home mode....is yours doing tha tyet?

 

Well I never hit anything around the intake to damage it. I ran the obd2 a couple of times without that code thrown. then I didnt drive my car for like 3 days and now it is there. What do you mean by limp home mode? The car seems to be running normal as usual.

Oh and the O2 sensor was 34.48 shipped off of ebay.

 

limp home mode=car wont go above like 3k rpms or itll stall

 

which O2 did you get off e-bay and how is it working for you so far ?