I have an '03 Maxima with about 156,000 miles on it and it started knocking quite bad and wanted to stall when it knocked but never stalled. I always use 91 octane and get my oil changed on time. I pulled a (pending) P0303 there was no CEL at all. After many searches on this site most people say it's more than likely the coil pack. Since I was going to have to remove the IM to get to the coil, should I replace all coils, spark plugs and fuel injectors while I have it open? I add in fuel injectors because they can also cause the misfire. I've already replaced both valve covers and replaced my spark plugs as well at around 127,000 miles. I plan on keeping this car for as long as I can because it's still in amazing shape and no rust (in Los Angeles). BTW, I was planning on buying Hitachi coils from Rock Auto. I would also get the spark plugs and fuel injectors from there as well.

I'm not the best mechanic, but I have take the IM off before, but that was about 6 years ago so I'm still a little nervous about doing it, but I know I can. But any reminder tips would be great.

So bottom line, should I replace all (3) Coils, plugs and injectors or just the one for #3 cylinder?

 

You have the right idea.

I would replace all coils with Hitachi's since it's a PITA to constantly take the manifold off and if you have the money, i would do the spark plugs while in there (NGK platnium if it was me)..

I don't see a need to replace injectors.

 

Great thanks. I was planning on the Hitachi coils and replacing all of them. Ok on the spark plugs, I guess even though they aren't that old it's good to replace them since I'm in there and they are that expensive.

Thanks again for your reply