I have an '03 Max SE a/t. I've noticed that when downshifting at highway speeds (45-60mph), especially when trying to pass, the engine hesitates up to around 3200 RPM. You can feel the engine trying to pick up, but something doesn't let it go. Then, it picks up. I've also noticed a random hiccup when stopped in Drive at a red light. The engine kind of skips for a quick moment then runs normally.

I should mention that I bought this car in February with 137k miles on it. Right now it has 145k. I have absolutely no idea if the spark plugs and ignition coils have ever been replaced. I'm thinking this could be the problem. No CEL on though. I hope someone can shed some light on this for me. Thank you all.

 

Let's start with some basics.

First thing to check is the spark plugs. The recommendation is every 105K miles. Maybe they have never been changed.

Check the air filter and see that it is not plugged up.

The coils are probably OK. If they mis-fire, you should get a check engine light.

 

Thanks for the advice. I'll start with spark plugs because I recently replaced the air filter (2 months ago). When it comes to the plugs, I've read I should stick with NGK, which are the OEM plugs. But I've also read the the iridium plugs work much better than the platinum ones. Is that true? Or should I just use platinum?

 

Use NGK brand, they work the best in Maximas.

Both the platinum and the iridium will work equally well in the car and you won't be able to tell the difference. Platinum plugs have a better spark but wear out sooner. Iridium plugs last longer but the spark is slightly less than the platinum. Nissan specified the platinum plugs for the car.

 

Good stuff. Thanks a lot.