98 Chevy 350 P0300 Code

I have a 1997 Chevy p/u with 110k miles with a 350 engine. It has begun back firing intermittently on while starting and throwing a P0300 trouble code (random/multiple misfire). I have checked the plugs and resistance on the plug wires and everything is normal. No other trouble codes show. I'm not quite sure what to check next. Is it possible the engine crank sensor could be faulty? Any suggestions would be greatly appreciated. I am concerned about a backfire damaging the catalytic converter.

Regards,

Phil

We had to replace ALL of the injectors, fuel control module and the left bank O2 sensor...a year later we had to replace 2 more injectors...then both cconvertors...if you have less than 80K miles on your rig...Chevy will replace BOTH of them for free...there is an 8/80 warrantee...call them

But before we did that we tuned her up...changed all of the plugs, wires, cap, rotor, thermostat, PCV valve, air filter, fuel filter. A year later, 2 more injectors were replaced and the left bank O2 sensor...and my wife still won't trade it in! Then we developed a leak on the left forward side (as you are loooking at the engine)...got pissed and added some leak stop and it stopped...seems that the lower manifold gasket is bad on these SUV's...seems like there are certain intervals that parts fail at...last month she got in a wreck...cost a little over $3K to fix...and she still won't trade it in!

One more thing GM has an 8/80 warrantee on their convertors...80,000 miles OR 8 years...they will replace them for FREE!!! CHECK INTO IT...they don't advertise it.

back firing could be caused by a fault in the crankshaft position sensor