2006 Maxima starts ok when cold. Really hard to

Go to the JustCommodores Forum and the guys there willhelp you with that. Here is the link...............

Forum VE Holden Commodore 2006 2013

is the air intake clear , new filter nothing squashing the intake pipe, how long does it take for the glow plug light to go out once you've turned ignition on ?

no car STATED, NO YEAR, OR Model or engine option (size)
turn on? (this word works ok for light bulbs) sorry !
cars dont turn on.
they crank, then start.
or crank start and stall.
is this car really so old it as a CARB? really?
i ask that because you mention sensors.
first post what you are driving, and then stated the symptoms. clearly
step by step is best.
engines run in stages from cold to warm then hot coolant.
each stage can fail.

Not really. If the problem was low fuel pressure it should take a long time to start cold also. Usually hard starting when the engine is warmed up is a coil or other electrical problem.
You can check fuel pressure before and after cranking with a special gauge hooked up to the port on the fuel rail.

I have the same problem with my F150 4.6. Long cranking when out door tempurature is hot. Engine temp gauge indicates normal engine tempurature. Looking for solution.

It could be the Crank Angle Sensor that has gone faulty. Works OK when the engine is cold but won't when hot.

Try checking your battery cables and terminals. Cables are made of copper which is a good conductor of electricity but the resistance goes higher when the temperature goes up so do a voltage and resistance test and see if that helps.

Is there a check engine light? Even if not, your oxygen flow sensor may be sometimes malfunctioning. Use an OBD-II diagnostic tool to see if you have any readings or error codes. You can borrow one from a friend or some auto parts shops will run that through for you - just give some a call and ask.

My car was having the problem I had my ingnition switch change, stater and a new battery and now it's fine.

crankshaft sensor may be going bad