Pontiac Repair: check engine code, spark plug wire, pontiac montana

Question
QUESTION: what does PO305 code mean for 2000 pontiac montana van?

ANSWER: Hi there;

that code is for a misfire cylinder #5 which is on rear bank of the engine against the fire wall the last cylinder at the back on that bank.


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QUESTION: what does it mean is it a problem with engine or is a spark plug?

Answer
It can be either. the most likely cuase is a spark plug wire or a plug. BUT it could be a fuel injector or an engine mechanical issue where the engine is lacking compression due to a broken valve spring or a worn out cylinder wall sticking piston rings worn out camshaft and on and on. guessing at what's wrong is not the way to fix it. It neds some diagntics done to it other then pulling out a code from the engine computer.