Pontiac Problems? Ask a Mechanic for Answers ASAP
Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.
Before you replacing anything else, scan the computer system and see what the actual fault code and or codes are that should be setting, post back with them and we can work from there.
The very most common cause for the code P0300 to set on this engine is usually a restricted catalytic converter. You can verify if that is the cases by loosing the exhaust at the manifolds till you have a healthy leak and then take it for a drive. If its restricted the power will return and the code should not reset. Try this before you replace anything.
Have you also made sure there are no engine vacuum leaks? It would be a good idea as well to go ahead and run the compression test as well along with checking the fuel pressure while the problem is occuring. Check these things for me and we can work from there.
Maybe but first you need to see if you have injector pulse at that injector. You can check injector pulse with a standard 12 volt test light. Place the test end on the power side of the connector with the injecto plugged in and the ground end on the other wire and crank the engine over. If the computer is providing pulse the light will flash while cranking and running. Check this and let me know and we can work from there. Yo also need to make sure you have spark and compression on this cylinder as well.