Could well be the O2 sensors or kne of them at least, not uncommon with aftermarket exhausts.
Once you get the code post it up for more help, you can get it via the pedal dance -
Confirm that accelerator pedal is fully released, turn ignition switch “ON†and wait 3 seconds.
Repeat the following two procedures quickly five times within 5 seconds:
Fully depress the accelerator pedal (HARD).
Fully release the accelerator pedal.
Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
Fully release the accelerator pedal (while the CEL is still blinking)
Wait about 10 seconds.
Fully depress the accelerator pedal and keep it for more than 10 seconds.
Fully release the accelerator pedal (The CEL light will continue to blink).
Turn ignition switch to “OFF†position and now you can startere is a quick way to reset your ECU. It is also known to clear codes thrown, and turn off the "Service Engine Soon" Light. It's a little tricky, but works.
Confirm that accelerator pedal is fully released, turn ignition switch “ON†and wait 3 seconds.
Repeat the following two procedures quickly five times within 5 seconds:
Fully depress the accelerator pedal (HARD).
Fully release the accelerator pedal.
Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
Fully release the accelerator pedal (while the CEL is still blinking)
Wait about 10 seconds.
Fully depress the accelerator pedal and keep it for more than 10 seconds.
Fully release the accelerator pedal (The CEL light will continue to blink).
Turn ignition switch to “OFF†position and now you can start the car.
The CEL light should be gone.
the car.
The CEL light should be gone.
Useful to have a mobile phone, firstly to time the pedals and secondly to record the code