So with my car it's supposed to unlock when i pull handle as long as I have my remote. Once in a while I notice it won't work. So if it won't unlock after two tries I just take out my remote and unlock it.

Plus sometimes when I push the button to start the car it starts but then there's a message that says "no key detected" but it still drives.

Or other message is "Restart now or no key is detected"

Could it be low battery in remote? I thought maybe my phone could be interfering so I keep both in opposite pocket.

It's not that annoying but  don't want to be somewhere and it won't start. 

Yeah, id say the battery in the remote is getting low. Mum has that same issue with her van

It looks indeed as a weak battery, but not 100% convincing. The reason is, it works when you press the key.
So other cause may be a bad contact in the car installation, namely the 150kHz transmitting loop antenna (made as extra wire loops put into the car harness). The bad contact on the antenna may cause the transmitted signal to be too weak.
Or the ferrite rod antenna within the key could be broken (after it had fallen down,...), or some similar fault in the LW receiver there.
Yet it could still be the weak battery causing the key receiver loosing gain.

The thing is on purpose designed with limited signal strength, in an attempt to control the working distance of the system (it is the simplest method - uses pretty clean signal strength as a measure of the distance, if the transmitter and receiver properties are known, but as described in some 2000's EDN journal and now confirmed on modus operandi of many car thieves, not that much secure). That means it is very sensitive to any minor fault causing even a bit weaker signal.


So first you may try the other key you should have with your car. If that works OK, the car side is for sure fine (although SW-wise each key uses separate data structures in the car, the HW is obviously only one, common for all keys).
Then try to read out the car diagnostic codes, they may suggest something.
With some systems, the key is sending some error codes to the car (like low battery warning, RSSI for the LW,...), which may direct you to the real cause. Definitely there should be some diagnostic parameters to indicate any problem inside of the car (antenna health,...)...
Don't overlook electrical problems seemingly unrelated to the 150kHz - the antenna wire is bundled into the other wiring harness, so there is strong coupling. So something ill in some other wires may influence the 150kHz link as well...

Ok, I'll have to try the other remote then. It's odd because sometimes it works fine and then suddenly it doesn't, then it does again. Also you would think if the car won't unlock when handle pulled that the button on the remote wouldn't work either, yet it always does.

I did find there is a spot in the center console I can put the remote and even if the battery is dead the car would still start.

Also you would think if the car won't unlock when handle pulled that the button on the remote wouldn't work either, yet it always does.

Unlocking by the handle needs the communication to work both in the LW (from the car to the key, to send authentication query), as well in the UHF (from the key to the car, to send the response).
If you press the button, all goes from the key to the car, so just using the UHF link.
So when there is something making the LW link not working properly, you get exactly the behavioryou describe. And because how the LW link is designed (using signal strength as a means to check the distance), the "something" could be anything from a wiring fault influencing the transmitter antenna loop, broken receiver antenna, till just weak battery in the receiver (the key).

The UHF link (key to car) has way less predictable signal paths, so it is designed with plenty of margin, so until the microcontroller in the key is still assembling correct pattern, the transmission works even with very weak battery.

I did find there is a spot in the center console I can put the remote and even if the battery is dead the car would still start.

There is direct RFID type channel, which works only over few cm, but does not need any battery in the key.
If that is working correctly, the odds are (if the maker was cheap and so uses common antenna for the RFID, as well as the LW link inside of the key), the key ferrite antenna is fine so the culprit could really be just the battery being weak.

Before replacing the battery, make sure you will be able to resynchronize the key with the car. One of the security method used there is based on a pseudorandom generator scrambling the data send over the UHF, so any command message wont be valid again (usually with 2^32 or even longer cycle). In order to work, these generators must be in sync between the car and the key. Removing the battery may reset it in the key, but the car side remains in its progressed state. So the remote wont work, until you align them back together. The procedure is exactly described in the service manual, sometimes even in the users manual, but it tend to differ among car brands...