You don't need people trying to fix it - you need people to find the problems.
A friend was telling me of his company's experiences being drafted in to help fix a major project after it went live
His boss had an excellent reputation for not panicking.
There was a big meeting - sorry a meeting with lots of decision makers making decisions.
The conversation went a bit like
Him: "what is the perceived problem and what evidence is there for the root cause"
DMs: It is slow - we are rewriting the programs
Him: What evidence do you have?
DMs; We are rewriting the problems.
Him:What makes you think it is the programs and not the database.
DMs: We have lot of coders.
Him: Can we get evidence on 1) database 2) CPU hot spots 3) locking... I'll send my team home until tomorrow morning
Next morning:
Him:It looks like evidence there is a database problem.
DMs: Great - we'll change the database
Him: Can we get evidence on where in the database it is slow. Is it slow disks, or a bad index?
DM: We'll change the programs to work round it.
Next day:
Him:It looks like the indexes have been badly designed and we are missing some...
If you want to use your coders, they can fix the application logic and implement field validation.
etc