Fault codes help

[Eddy]

Hi Folks, Recently joined and i have been searching around a bit for these fault codes but i could do with a bit of help please identifying the exact problem?
Purchased the car a couple of months ago and i have been told the 02 sensor is playing up because it has a 3" downpipe with decat so the sensors are getting to much flow? (new sensor fitted 2/4/13 )
I have also changed the temp sensor because of code P1296 but code keeps coming back?

1, P0130 Generic 02 sensor circuit malfuntion ( bank 1 sensor 1 )

2, P0135 02 Sensor heater  circuit malfuntion ( bank 1 sensor 1)

3, P0036 H02S bank 1 sensor 2 heater circuit

4, P1296 Cooling system mafuntion

Car is golf 1.8t with a stage 1.5 custom remap by r-tech and it is giving crap mpg
Any help would be much appreciated 

[Eddy]

Nobody ?

[mike1990]

1 - Check the wiring, or replace o2 sensor

2 - Check wiring, or replace o2 sensor

3 - Check wiring or replace o2 sensor

4 - Coolant temperature sensor or coolant thermostat

[Eddy]

It had new 02 sensors about 6 months as well as thermostat and I have just replaced the temp sensor. I also forgot to add that sometimes the car kangaroos a bit when pulling away? Just wondering whether it could be anything do with the maf sensor?

[mike1990]

It had new 02 sensors about 6 months as well as thermostat and I have just replaced the temp sensor. I also forgot to add that sometimes the car kangaroos a bit when pulling away? Just wondering whether it could be anything do with the maf sensor?

Yes, I'd be checking the spark plugs, coil packs and the MAF sensor for that. Try and clear the codes, go for a drive and rescan and see what comes back

[Screech16v]

Try unplugging the maf  for the kangarooing,car wont boost when unplugged but it should be smooth,or clean the maf and throttlebody first

[Wazzzer]

Were the codes cleared after the parts were replaced?

[Eddy]

The mil light was on when i purchased the car so i did a scan and it only showed up the 02 sensor which the guy said is on because it has a 3" downpipe with decat so there is to much flow going past the sensor?

I unplugged the maf sensor plug earlier and it seemed to run a bit better when i took it around the block? (Got a 2nd hand 1 on order which is fully working)

I also cleaned the throttle body today and to be honest it was pretty clean to start with.

Going to order a thermostat and change that as i have already changed the temp sender?