Nissan Repair: 99 Maxima code p300, running rich, exhuast, fuel regulator

Question
99 Maxima 3.5L, standard transmission, 223,000 mi. Been running great, suddenly started running rough and picked up code p300. Cleared code and it came right back. Cats are running hot (smell) and is running very rich - you can light the exhuast with a torch! Starts VERY hard. Cleans up and runs strong over 4000 rpm.
Stuck injector? Fuel regulator allowing too high of pressure? or?

Answer
Hi Frank -

P0300 is a multiple misfire. This may mean that instead of just one cylinder missing, it detects a random misfire, which of course, makes the exhaust very rich.

Try checking the coils, or spark plug wires. When was your last tune up? Should start with that to eliminate the obvious. Distributor cap and rotor too.

Because the ECM is detecting a misfire, it may not be fuel related.

Hope this helps -
aloha
calvin