The 2004 Maxima uses the 3.5L V6 and has 6 independent ignition coil on plugs (Also called "C.O.P"). With this specific 2004 Maxima model, we highly recommend that all owners check the main ground before installing new coils. The main ground is the big ground cable that goes from the negative cable on the battery, and connects to the transmission. It was common that the connection on this ground deteriorated overtime, causing all sorts of electrical problems with the 2004 Maxima. The 2 most common problems that the broken grounds cause was a fried PCM/ECU (main vehicle computer) and fried ignition coils. The coils from a bad ground look like they have big blisters on them, or even bubble-like swelling. While the ignition coils are not included in any part of any service interval in the 2004 Maxima, these coils can still wear out over time and fail, causing a misfire. Common OBDII codes for a misfire are P0301, P0302, P0303, P0304, P0305, and P0306. What many owners have experienced is more than one coil failing within a short period of time. If all of the coils are old, and one goes bad, then the other coils are near the end of their service life. Replacing all 6 is always the best decision. These can be very expensive locally. That is why we have the entire set of 6 for significantly lower prices than the auto parts store, and shipping is included in the price. Continue to find the ignition coils you've been needing at an actually affordable price.

 

 

The 3.5L VQ35 engine used in the 2004 Maxima is a great engine. It uses independent ignition coils and there are a number of reasons why they can fail. The number one reason is old or worn out spark plugs. As spark plugs wear, the gap increases. This will increase the resistance, forcing the ignition coils to work harder to perform the same operation. Replacing the spark plugs at their proper replacement intervals will keep your coil packs in good shape for a long time. Another reason why they can fail is water or coolant leaking on them. This is obvious, but easy to miss as owners may not notice when a coolant hose is about to burst. Check your coolant hoses is a good practice that will prevent other issues down the road. Water can also get on the coils by carelessly washing the engine bay with a high pressure nozzle or a pressure washer. While you can wash your engine, it's important to not point the nozzle anywhere near the coil packs. The connectors have a seal inside of them, but high pressure water will get pushed past the seal damaging the coil. We recommend to cover them or be extremely careful while washing the engine bay. The last common reason these can fail is something out of many people's control, and that's the climate for the region you live in. If you live in a very humid climate, the ignition coils will simply just not last as long as someone who lives in a dry climate. Humidity is the enemy of these ignition coils, so if you have friends or family in dry state with no issues, no need to think there is something abnormally wrong with your Maxima. Earlier failure is normal in humid climates.