P0300 Multiple Misfire issues with 01 Suburban

[artmolina]

I have an 01 Suburban that gives me a P0300 OBDII code and 2 other codes, I erased them but they were for... Bank 1 and Bank 2 Sensor 2 on both banks. The exhaust smells bad but not like rotten eggs. There is no smoke out of the tail pipe. I have replaced both cats and all 4 O2 sensors about 2 weeks ago. I checked my plug wires and fuses.

I have a couple of questions....

1. I noticed someone had said that there might be trash in the fuel rails, how would I check this out??
2. How would I isolate the misfired cylinders??
3. Could those O2 sensor have gone bad that quick??
4. Is Sensor 2 the the sensor after the cat??
5. What causing that nasty smell out of my tail pipe?

I know it's alot to throw out there but I'm lost..
I need to trade this thing in for one of those new Tahoes, nice....
Any help would be greatly appreciated.

Thanks
Art

[bustinjustin41]

My Guess would be fuel pressure regulator.....you didnt give much to go on but the last few p0300's i have seen on these trucks were regulators