Need help,my forester is playing up,sometimes when im driving I push down on the accelartor and theres no power,CEL light comes on but doesnt flash a code,just pauses for abit then goes away then the cars back to normal again or sometimes I have to chop down gears just to get going again,also when im sitting at the lights the revs just climb upto 2500 revs. If anyone can help me with these problems it will be much appreciated. Thank you