How do I know if I'm running rich?
 

How do I know if my car is running rich? Would I smell fuel etc?

At idle an no load, or WOT while driving?

I suggest you buy a gauge if you're running anything that would lean you out, Nitrous or boost.

Off the top of my head:

1. raw fuel smell in exhaust
2. black carbon deposits on spark plugs
3. eventual fouling of o2 sensors (so the CEL witll come on)
4. eventual plugging catalytic convert (trigger CEL)
5. poor gas mileage

Ok I have none of these symptoms, we just did a compression test the spark plugs looked fine. No trigger of CEL for as long as I could remember actually I had a bad front O2 sensor which was replaced and since then no CEL. No CEL in reference to the cat., and mileage is decently good 260-300 miles mixed city and highway.

I guess I should have asked earlier - why do you think you are running rich?

Well my car is OCCASIONALLY starting hard, keyword occasionally because it happens once in a while which is more than enough to get me worried. Sometimes I hear a loud pop from the exhaust which indicated fuel. So a reputable mechanic that I'm friends with recommended leaky/weak fuel injectors, and implemented that I may be running rich. Which is why I proceeded to pursue knowledge of common symptoms of Maximas running rich.

I got ya... see what you might have a leaky injectors but with a slow leak - so when your car is sitting overnight/few hours or whatever, the fuel drips and enough accumulates to cause hard starting and the symptoms you describe. Once started however, the injectors are not in bad enough shape that they cause any problems - know what I mean? I think I have the same problem - occasional hard starts - no problems otherwise, no mileage drops or other symptoms to suggest that its always running rich.

But now here's the thing how can I check the fuel injectors to see if they are bad?

I am not sure to tell you the truth - which is why I've left mine alone too.