Hpi nitro rs4 help needed asap

[ginger2013]

Hey guys as some of you might know I have recently sold my rs4 but had a phone call Christmas day of all days going mad as it starts runs up then revs fully then dies any ideas what they could of done it worked perfectly an hour before they had it
I haven't got it in front of me and havent seen it since they had it they said they havent touched it but by sounds of it they aint got a clue

 

[Jsmith]

Air leak. Pinched line. Pin hole line.
Just what pooped in my head.

 

[Non Crimen]

what pooped in my head.

I don't know what/who would do such a thing?!