Postby smj999smj » Tue Sep 04, 2012 12:37 pm
If the rear sensor was bad, it would usually throw a code. Exhaust leaks are easy to find, but you would have probably heard it. There really is no "ignition module" on the VQ engines. The power transistor is built into each coil pack, the crank and cam sensors signal the ECM, which "tell" the coils to fire. In essence, the ECM is sort of the "ignition module" and I highly doubt that's your problem. Coil packs and crank and cam sensors will, likewise, also "usually" trigger a trouble code. If there are no trouble codes and no exhaust leaks, there's a good chance you just got a cheap catalytic converter. I've never dealt with Muffler Express, so I can't really comment on their products. I have seen new "off-brand" and "no-name" converters cause catalyst codes soon after they've been installed. If you can't afford a genuine Nissan converter, your best bet is an established name like Bosal or Walker. If you live in California, make sure the part is CARB certified. As far as the anti-fouler med, Google it and you should find the procedure and part numbers for the anti-foulers. Spark plugs and O2 sensors use the same thread sizes (for 14mm and 18mm); the mod involves opening up the end of the anti-fouler so the O2 element can pass through. It's not a guaranteed fix, but it's a low-cost gamble as anti-foulers are only a couple of dollars and it has worked for many.