ok when I was going to work today I started my 2000 rs up and it idles fine. I let it warm up for about 20 seconds before taking off. when I would push on the gas I my car acted like it was no getting enough fuel or spark. It only happend when the gas pedel was half way down. When I put it almost all the way down it seemed fine. It was like the power suddenly came back. What do you think It could be??????????