Overheat or sensor issue

Okay, so this has been affecting my car since I got it and a few things have come up in the process so I am not sure whats what and whats causing what.

That being said lets get to it shall we? I will try to be as descriptive as I can and include as much info as I can.

So from the beginning, about three months ago I bought this car, I was told it needed a new thermostat cause it was overheating. So I had a new one put in on day one. Also the radiator fan was not responding properly to the electrical system. Was told that when pushing the relay down it would let the fan work but when let go of downward pressure would stop fan from working. I needed the car to be worthy of highway travel to move to another city right after buying the car so I had a mechanic hard-wire the fan to a switch installed into the dash so I could at least flip it on when needed or leave on all the time while operating. Tada! Car now worthy of highway travel. Drove and moved to new city but on the way in February was cold and with no cardboard in front of radiator the car got so cold I needed to stop, now and then, and let car warm up so I would not freeze. Moved to new city now start work as courier all day everyday.

So now I got this car to new city and its working fine had some front end issues but piece by piece taking care of it. In the mean time when would forget to throw fan switch on car overheats, has a loss of power and fluttering while trying to accelerate. I assume this is a fail safe of PCM registering very high temperatures in cooling system so it drops power to protect from excessive overheating until finally too much heat and just stalls out will not start for about twenty to thirty minutes when it has cooled off then will start fine and run fine again. So I work all of February and March and April. Now we into warmer weather and its doing the same thing but this time fan is on all the time and car sits idling for a bit then when try to go it does same loss of power fluttering while accelerating. Tried a new MAP sensor, read codes for engine light as:

P0335 CHEVROLET
Crankshaft Position Sensor 'A' Circuit Malfunction

P0342 CHEVROLET
Camshaft Position Sensor Circuit Low Voltage

P0480 CHEVROLET
Cooling Fan Relay Control Circuit


So these codes I read about a week ago or so. I have got plans to get the position sensors replaced but I am having the issue with the loss of power while hot. Temperature gauge shows very inconsistent temps but relatively well as in they are not jerky changes as they are more fluid changes in position on the gauge as one would expect to see with a steadily climbing engine temp when first starting up. That being said a buddy who knows a lot more about cars than I do cause he fixes in spare time for others a lot, said he thinks the temperature gauge not showing accurately that is to say that he thinks its showing slightly cooler temperature than actual temperature. Either way, still problem with engine overheating and loss of power while accelerating when engine is warmed and operational for even just twenty minutes today.

Any help would be appreciated. If need more information I will try to get it to you in timely manner. I need my car in order to work and earn a living. It is running fine right now but it is still kind of cooler weather and when gets warmer I am afraid will not work at all at that point. I need to figure this out before summer temperatures hit! And

Edit: so it appears to me now that is the cars issues happen mostly inner city speed at around forty miles per hour and faster is when it tends to run fine.

Also, today I flushed the cooling system with a radiator flush agent then straight clean water twice and now running with straight water. My region is above freezing temperatures overnight so no worries about that for now. But, after the rad flush the car seems to idle higher than usual, however; I have not known this car for too long let alone the fact that I have never seen or heard this car running at optimum performance yet.

Again; also; it seems that if I put it in neutral or press the clutch and then rev high it seems to not mind that at all except for the obvious timing and firing issues caused by the two faulty sensors I presume.

This makes me think it is more of a sensor issue then merely an overheating issue. Please correct me if I am wrong. I would like to only spend what I have to to keep it going so I can earn more money to fix it more. It is a decent car but has not been well looked after for the past few years or so from previous owner. It just needs some TLC.