P0305 2004 Pontiac Montana

Question

Replaced spark plugs, wires, ignition coil and module and still has the same problem and also replaced fuel regulator. Why am I still getting the same P0305 reading? It will run smoothly for about 10 miles when you erased the reading/reset and then the engine will be shaky a little bit when idle and the p0305 code comes back. What else should I do?

Answer 1

P0305 Misfire number 5 cylinder

Misfire number 5 still persist? Is there any coolant loss. Number 5 cylinder is located right at the edge , you would need to do a visual inspection of the lower intake manifold, check to see if there is any coolant seepage leaking

This is where the number 5 cylinder is located at, these gasket here tend to leak coolant into the intake manifold. and having cylinder 5 here this is where you need to check. pull the sparkplug out and check its condition if its wet with coolant or water, the intake lower gasket  is the cause