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Electrical light keeps coming on and going off!!!!

Can anyone help. Electrical light keeps coming on and going off in my 172! It's doing my head in now. Goes off sometimes once ignition is turned off and on, and stays off for a while and then comes back on.

Drove to the garage yesterday with the light on, pulled up to get fuel before I got there, get back in the car and its gone off! Typical. Fault codes were saved into the system which was good anyway. Here are the faults.

-P120 Tps/pedal position sensor
-P130 O2 sensor bank 1
-P135 O2 sensor heater sensor malfunction bank 1 sensor 1.

If anyone has any insight into this it would be much appreciated. Sorry if this subject has been covered before. Many thanks, Jack.
Ok, have cleaned all the fuses ect, was some corrosion. Just taken car for a spin and light had came back on. Turned off ignition, went off. 2 minutes later back on! I don't know a lot about cars but if I can solve this myself I would be chuffed!
Got the ECU cover off this morning to see if it had cut through the wires. The wires have already been wrapped in lashes in tape. Maybe I should strip the tape back and re tape and insulate. Got a 2 hour trip ahead of me now so hope this light don't come on!!! Anyone in the Herefordshire/Shropshire area who may be able to lend me a hand? Got my Cooksport springs to put on too so will have to get it into a garage anyways so might as well ask him to have a look!
Alternator on its last legs. I had the same problem, if you buy new I recommend going direct to renault. I had problems getting the correct one from motor factors and ended up paying just under what what renault want for a standard unit.

I had 3 wrong units , Bosch and 2 x Valeo and they finally got it right with a Lucas unit. Just FYI so your not pulling your hair out in the same situation as I was in.

Simple test for alternator is get a multimeter , live onto the power outlet on the alternator then a earth it should be putting out around 14v and the battery should read around the same.
Funny both of you have said alternator. Have searched forums for hours now and there as so many different things it could be? But like you said ill get that test done. Should I have mentioned it goes into limp mode and won't go above 3k revs?
I have a decat so the EML light is always on too, so for all I know this light could also be trying to tell me something.
Same symptoms as I had. The engine will start to splutter (not firing on all cylinders ) when the alternator is failing to charge the battery and eventually it will cut out.

I found it would start misfiring when the battery got below 8v and in my case , sometimes, revving it high would spark the alternator into life a little bit.

Easier test is to make sure your battery is producing 12.5ish volts , start the car and turn everything on , lights , heaters ect and if this causes the battery light/ misfiring to happen it's more than likely the alternator.
Thanks for your help, ill give it a go. Just managed to do a 2 hour trip will no problems what so ever! I'm amazed! My exhaust does splutter a lot now and again and pop and bang like mad! I love it, but at the same time there is a noticeable power loss from acceleration, which does eventually clear after enough acceleration and about 20 pops and bangs. Next time I go out to the car I will try what you've said, thanks.
When I took it to the garage the other day they said the pops and bangs and spluttering way due to my decat and straight through pipe, I thought it must be someone else effecting it.
  16v 1.6 Clio MK2
Yer alternators either fail out right or have momentary life before completely crapping on you in the best moment possible lol.

best thing to do is get the part number of it so when it does go dead u maybe have 1 already lined up. Or just replace it now before it becomes a real problem
Well thought I'd fixed it! Managed to do 500 miles without it coming on. ECU cover had started to dig into the wiring so took cover off and taped up the cables and used a couple of cable ties to keep the wiring together.

Turned ignition off when it came on, then the light went off! So it's off again now but don't know for how long!