Problem with a 1.8 Corsa

I have a 2009 corsa that drives it and everything is going well only that after a while the car stays in 2000rpm and stops accelerating also turns on the foquito of the car with a crossed key they told me that it was the immobilizer system but if it were this simply not start it also says that this fault is cause What could be?

Hello friend, that car comes with motorized acceleration body, that is electronic accelerator? If so, check it because the butterfly potentiometer is usually tight and produce that fault, it is corrected by placing a spacewy washing so that it will work lightly, tell us how you are doing, hug.