CPU 100% - Needs to be brought down urgently!

I have a wordpress site that is built on a Linux cloud server with plesk installed. The site is live, but not getting much traffic and there is plenty of space on the server, however the CPU is constantly on 100%,

I have spoken to the hosting company and they have said the cause of the issue is due to php scripts not closing and this may be because of malware or some bad code somewhere. The hosting company has said that this is all the details they are able to give me. Ie they cannot tell me the path of the files or if it is coming from any plugins etc.

Me and the developer have searched the site and we found some malware files and removed, I restarted the server and the CPU went down, however it has gradually gone back to 100%.

I need someone who can completely fix this issue so that it does not come back. Before this issue the CPU was about 10%. I would like to get back to around that area.

Please remember, the hosting company have provided me with all the help they can so I cannot go back to them for any more requests