My car is misfiring pretty bad on cylinder 1 Code P0301. Here is a list of what i have replaced so far:

Coil Pack, spark plug, Spark plug wire, o2 sensor(all of them)

The only other thing i can think of is the fuel injector. I guess i will try that next. If anyone has any other Suggestions before i have to start throwing down some serious dough i would greatly appreciate it.

 

Is it a stock cam? Check the coolant level, make sure it's full w/ no air bubbles. Cylinders 1 & 2 are the first two cylinders to get hot @ the head because of an air pocket caused by low coolant. Probably not the issue, but worth a look.

 

Swap the injectors between #1 and #3. Rail-end
injectors foul first, if it's a sediment problem. And
I have seen that on a couple of cars.

 

Hate to say it, but last time I had randommisfire codes it was valvesprings...the passenger side springs were (6 out of 8) so soft I could push them down by hand...check it out.
(I was convinced it was the issue jimmyblue described, until I changed the fuel rail and it was the same)

Good luck.

 

Thanks for the info. I guess i will swap the injectors when i get back in town tomorrow. I hope thats the problem but if not i will check the valve springs. As for the cam it is a custom crower mild cam in a 2002 corvette motor with 10,000 miles on it. It only misses some of the time so i dont think the motor is bad or anything but i am almost stumped at this point. Thanks for your help. Let me kow if anyone else has any other ideas.