I'm not a mechanic / technician but I am wondering if cylinders 1 and 4
come off of the same coil in the coil pack . As far as I know the coil pack has
(2 coils inside ) with 4 towers for the spark plug wires
Bad spark plug, bad spark plug wire
Dirty fuel injectors or spark plugs
It could just be a bad spark plug wire or the spark plugs need changing.
Your 1996 Pontiac Grand Prix will experience cylinder misfires when one or several of the spark plug wires are bad. A bad spark plug can also cause the problem.
There would be six spark plugs for a six cylinder engine. One for each cylinder. Unless it is a diesel, then there are no spark plugs.
I'm not a mechanic / technician but it might be the spark plug , spark plug wire , not the proper air / fuel mixture to that engine cylinder , and there are probably other causes
Check the threads for the spark plug, Im betting it was either crossthreaded or not tightened enough and worked itself out.
Worn, faulty or dirty spark plug; cracked or worn spark plug wiring or loose connection.
sounds like a cylinder misfire..check spark plugs and wires..usually a code will show which cylinder it is, should replace all though
Bad spark plug or plug wire or one or both valves leaking or stuck. Time for a compression check or spark check.
Most likely a bad coil (each cylinder has one) located at the top of each spark plug
Most likely a bad ignition oil. Each cylinder has its own coil mounted at the top of the spark plug