Replaced crank and cam sensor on a 2004 altima 2.5 but the trouble code is still telling me the crank sensor is bad.

If you have a OBD Code reader you can do a clear of the codes.
( if not then go to autozone and ask for them to clear-it's Free)
You may also just disconnect your battery for 5 mins and reconnect which may clear the codes.
Just clearing codes won't fix the problem if you really have a cam sensor gone bad,(this happens) this can make a car act bad.
Both the cam and Crank sensors report to the computer if they feel sick, then the computer stores the codes. IF the Cam Sensor needs replacing it's not so bad to replace BUT the Crank sensor is buried under the timing belt cover and that can take some doing, Either may be by a profession if you are not one. Parts could cost under $50 or so.Labor not bad for the cam BUT much more for The Crank sensor. It's always good to replace the Crank sensor if the timing belt Kit-and water pump is done.

One crank sensor. It needs to go on a scanner. Both sensors are probably OK. Your problem is most likely the timing chains or guides. If ti were the crank sensor, it wouldn't start. Cam sensor would throw a cam code. Correlation means the crank and cam are not in sync. If you have VVT, it could be the actuator.

replace the crank sensor if it is a 2.5 ltr or cam sensor if it is a 3.5 ltr

how to? who can, where is it? ask a real question.
Ill answer how can it tell , its bad.
these cars can have 2 or 3 engine options, to work on any
cars engine, you first need to find out, what engine it is?
mine is 2.5L V6, my last one , was 2.0 I4 .

why do you think its bad? is the ECU sending trouble codes, DTCs
for this sensor? either running or cranking, if not ,its not bad.
easy huh?
here is the scan list P0355 is the CKP sensor (crank)
got 335's? is that it?
The fact is the ECU is real adept at reporting this sensor bad.
even if it misfires 1 in 10 times. really

http://www.fixkick.com/CEL/DTCs-1.pdf

These are a well known failure point for this vehicle and engine. They are currently on there third redesign to help solve the frequent failures.

the first thing to do is see if there are any trouble codes in the computer. If you see P0340

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Have the vehicle scanned again to see what codes you get. Its possibly either mismatch firing order with the coil boots or hairline cracks in one or more of the spark plugs. I'd remove them and closely inspect the ceramic for damage, even the most minute crack can cause an arc. Then there is always the possibility of faulty sensors.

There are so many sensors on cars now a days its hard to say, i can take a guess,you may need cam and crank sensors and the other sensors may be the oxygen sensors, this car is a 2005 this many sensors going bad at once is crazy, even with 100,000 miles on it, i would have a second reapair shop or dealer look at it,

check the pin connectors to see if there split open and not making contact

This engine has both. Nissan recommends replacing them at the same time, I think your local Nissan dealer will tell you the same thing.The cam and crank sensors are in the rear of the engine.Looking from the drivers fender find the right rear corner of the valve cover and look straight down the back of the head. the cam sensor is 3-4 inches down from the valve cover gasket surface.the crank sensor is basically straight down from the cam sensor but much harder to see. it is just above the oil pan gasket surface...

A common problem on this vehicle is failure of the Crankshaft Position (CKP) Sensor. Failure of the CKP Sensor will result in the vehicle not starting. The cost to repair the CKP Sensor is estimated at $29.13 for parts and $26.00 for labor.