Is it the gas pedal

[Roddierm]

Hi guys got a red lightening bolt on. I know it's the throttle control. Is there a chance it's the gas pedal as this doesn't seem to fully come back to the rest position when you take your foot off the gas. You have to put your toe under the pedal to lift it back. Is there a spring or something that you can replace or is it a whole pedal box. It's a 2005 2.8Crd. cheers in advance guys