Hard to start and loss of power

Okay now the camshaft sensor replaced the car runs, although it seems after starting the car idels rough for a few seconds. Sigh

Cleaned IACV, problems resolved. Thankyou!

I have a nice 02 Maxima, that I really like but lately it has problems starting. It cranks over for like 30 seconds before firing. Some times it starts right away but more and more it takes a while to fire. It seems to run just fine afterward, not noticing anything else. But I'm getting worse gas mileage than normal as well lately. Concerned as to what this might be. The battery is fine and cranks strong it just doesn't start right away. Runs smooth and no issues idling once started. Wonder if it needs a tune up? What are some things to look into? Does Nissan have any particular things that seem to need changed at 100,000 plus that might just been worn out and effecting performance? Thanks

Just replaced motor in my 2002 nissan maxima. Now car is hard to start and rpm hand doesnt work anymore. Went to dealer and they said change cam and crank sensors. I did that and still no change! I even changed fuel pump. What is really the problem and how can I get this fixed before I go broke?

Ok, so for a number of months, I've noticed an occasional difficulty getting the engine to run while cranking (turning the key). It would sometimes turn over a few times and then start right up, but other times it may just turn and turn without running. I also see it occasionally try to kick on and immediately die or give up. But usually upon a repeated attempt, the car starts. Once it's started, It runs fine. I hear no strange noises or knocking. It doesn't sound as if it is misfiring. I recently had to replace my alternator. The battery has been tested recently also as my starter went out. I just put a new starter in because it stopped turning. But I still have had the issue with the car taking a while to start up. It may start up fine, or it may turn and turn and do nothing. I'm posting this because the problem is occurring more and more frequently. Almost every day. And also, because I haven't got the finances to purchase a lot of tools to test certain components with. I'm planning on putting new plugs in, but I wanted to check with you guys and see what the most likely culprit is. Sorry for the book, thanks in advance.

Thanks for the quick reply. So here is what I've done and also some other details which I somehow omitted when I pasted the first post.
I checked spark at all plugs, all seems fine there. I replaced plugs anyway since I was inspecting them (this did not affect the issue it seems). I convinced a parts store to check the fuel pressure before starting, while running and after shut off. They said the numbers were acceptable. I cleaned the throttle body assembly thoroughly and checked vacuum lines for leaks by spraying starting fluid around the area. I've tried spraying cleaner into the intake to achieve a quick start, but it seems to have no effect. So on to the previous details I left out. The CEL has been delivering a P0420 since I got the car over a year ago. I've never had issues with starting the car until the last few months. During the cold mornings, the exhaust would rattle when cranking, but that has ceased now. The only other symptom could be a rare idle problem when it is really hot outside. For the first few minutes of driving my car may try to idle very high in neutral, sometimes over 4000 rpm. But If in gear, I hold the brake. Also during this time, the tach could wobble up and down between 1000 and 1500 rpm in gear. When I drive around and get the motor "warmed up", the problem goes away. This is an uncommon occurrence and isn't going on right now. But in case it is related, I put it there. So as it stands, I have a fuel pump that supposedly works, a clean throttle body and working spark plugs and coils. I'm lost what next?

Recently, when I go start the car, sometimes it labors or takes a moment to turn over and start. Sometimes I have to retry, but rarely. Then when I'm driving, going mainly at slow speeds, after driving on the highway, I hear what sounds like a fan noise. It is subtle. But it sounds as if I can hear it turning, or turning more slowly, like around and around and my car is a bit louder recently. No overheating. Is this just a battery going bad, and wear and year on an old vehicle or should I be concerned something. Or two things are going out?

Okay. I will try to get the recording done tomorrow. I'll upload it when i'm done. I'll also have the whole charging system tested, battery, grounds to the body, motor and frame tested ASAP.