Help with these diagnostic codes?

Hi, recently bought a 225 trophy, and been having a issue with it past few weeks.

I had the car plugged into a Bosch diagnostic system and it came up with four codes, quick search on Google told me what they was, these are the codes and what I read from various sites about each code;

PO638; Throttle Actuator?

PO2502; came up blank on this one

PO0235; boost pressure sensor?

PO0530; something to do with air con?

Could anyone elaborate on those codes? And correct me if I am wrong on any of them?

The car runs absolutely fine normal driving, but every time I put my foot down, get into 3rd gear, CHECK INJECTION comes up on screen and puts car into limp mode, ESP FAULT then appears.

Turn the car off, then back on after few mins, and all is well again, and can drive it normally.

What I've done so far;
Changed plugs
Removed Throttle Body and cleaned (was very dirty inside)
Fitted KTEC's sensor brackets to the map sensor and vacuum hose on the throttle body (vacuum hose was originally held in by a cable tie :/)

The vacuum hose doesn't fit in the best as some of the clips are broken off on it.

I think a new vacuum hose will be the next port of call, as it may be letting in a leak or something.

Don't really want to go down the route of buying expense parts such as a throttle body or new coils, unless I definitely know that it will solve the issue.

Any help and advice on said issues would be great!

 

Thank you. Shall have a browse through now.