luiscompean

After installing bbk long tube headers and bbk high flow performance xpipe on my 07 mustang gt the check engine light came on and the p0300 and p0302 dtc codes came up now I know the cylinder two is suppose to be misfiring and maybe another cylinder also but all this happened tight after I installed the headers Nd xpipe. Does anyone know what could be causing this issue? And does anyone know how to check if the o2 sensors are working properly? I also have installed ford racing performance spark plugs. Any help and/or advices will be greatly appreciated

mx07gt

check if you plugged the coils correctly, sounds like thats the problem.

luiscompean

its not the coild because i installed them two days ago and the headers and xpipe i installed them about two months ago , i know it has to be either the o2 sensors or something that has to do with the headers and xpipe cuz everything was working fine before those two mods

luiscompean

but thanks for ur help mx07gt, also here's another detail, when i turn my car on in the morning it makes a noise like if the car was either letting pressured air out or suctioning air in from somewhere under the car.

2007VistaBlueGT

P0300 is random misfire. the DTC light will come on when ranodm misfores occur or the PCM can not identify misifing cylinder.

Possible causes.

• Camsahft position sensor
• Low fuel ( less then 1/8 tank)
• Stuck open EGR valve
• Blocked EGR passages.

One or more EGR passages may be blocked or partially blocked. If this is the case the misfire detection monitor indicates the EGR port to check for possible blockage.

Lito

You may be too lean, or may have a fuel pump problem. Using your SCT you can datalog fuel pump duty cycle, fuel rail pressure and if you want to check the O2's you can too, you will see them switching around 0.45V once in closed loop (up to after 60 seconds of startup depending on your coolant temp at startup)

These cars do not have EGR.

luiscompean

Thanks for your advice lito, but could I have fuel pump problem even tho the car hasn't reach 19k miles, it's almost a brand new car that hasn't been run on the track and only run twice over 100 mph it's not a daily driven car, like I noted before the only thing I hear different after installing the headers and xpipe was a noise from under a car that sounded like air escaping but I don't from where that's coming from, and also i think it might be the o2 sensors and I would like to find a way to see if they are working properly

Lito

I've seen pumps with less mileage fail or clogged filters that could cause your codes, the misfire occurs when you have a failure on the ignition side (coil, plug, wire, etc.) or when there is no fuel to ignite, if the ignition side has been checked I would check the fuel side.

An O2 sensor problem would trigger other codes, and they tend to trigger them easily, also, if you have an exhaust leak as you say what may happen is that the O2 will sense a false lean condition and start adding fuel. I've never seen a misfire condition caused by a O2 sensor.

I can't help you exactly on how you do datalog on the livewire because I have no experience with them but if you get me your strategy code I can make and send you a .DLF for you to datalog some stuff and check that out.

All you will need is to download livelink and transfer the .DLF file to the LW and set it to datalog.

I would do the following:

- Pinpoint the leak, use a rubber hose and with the car running try to look for the leak with one side of the hose searching and the other on your ear.
- Switch the spark plug & coil number 2 to another location to see if problem transfers to that new cylinder.
- Datalog the car to see any weird things.
- Take the car to a local dyno with a nice wideband to check AFR at WOT.