P0300 code help. Newbie

Question

Having all the typical symptoms. Hard start especially the first of the day an it rattles an sounds like alot of air is doing something until it warms up. Seems to run alright on streets. When heavier load its misfire an hesitate. Doesn't turn off. Or stall. Just real sluggish it seems. Not really overheating. Sometimes will act as if it wants too but stays in 200-220 range. Neighbor says clogged catalytic. Its a 400$ cat. Need help. If that isnt the issue. Then im just dumping money

Answer 1

HI there

A good test to see if the converter is the problem is to remove the O2 sensor before the converter, then drive the car. If it runs better and have more power then you know the converter is plugged. Removing the sensor gives the exhaust a place to go.

If there isn't any better power, then the issue isn't the converter, but something else like the mass air flow sensor or a possible problem with the fuel pressure.