Decision,decisions, decisions! Thats what it(airmanship, captaincy, etc ) is all about.
You have a torch,so go and look at the engine, fairings, exhaust, to see if you have any coNfirmatory signs( the exhaust b`cos you may have an internal leak, and you may see a difference). If you are pressurised and have an internal leak you may start getting fumes into the cockpit---OXYGEN?
Check your safety altitude , and your single-eng. cruise ceiling, if you have to shut one down.
Find your nearest safe diversion airfield and divert.
It may be a gauge problem, it may be an impending catastrophic failure, but it probably won`t get better.It may be prudent to shut it down early rather than end up having it grind to a halt just when it will cause you more embarassment.
If things got really sticky later you may be able to do a restart .
There really are so many variables, and guidance should always be sought from the Flight Manual; however, that list of emergencies is not always all-encompassing, so that is where you have to apply your own( or others) experience, and systems knowledge
Remember, it`s much better to be down here supping a coffee
WHILST AN ENGINEER CHECKS IT OUT, THAN UP THERE, when it`s gone from precautionary, to a full emergency.......
I`m sure others will have a wide variety of advice , as usual, but it would help if you were more specific regarding a/c type and area of operations.
Safe flying anyway....
