Is the fuse warning light present all the time or only when you turn on certain accessories ?
I used to have a ’ blown fuse ’ warning light flicker sometimes when my engine cooling fans kicked in. The fuse was fine but the solder joint to the rear of the fuse box had cracked and I cured it by reflowing all the joints. I would try and identify which circuit is affected then examine the relevant fuse box with an eye loupe, you have to look really closely to spot the solder cracks.
Code 33 relates to the ‘Injector circuit’ Haynes manual says it indicates ‘an open or short circuit’. Seeing as you don’t have a check engine light illuminating it could be just a stored code that needs erasing. I’d try disconnecting the battery for a minute or two ( as Larry pointed out, make sure you have the radio code !! ) if the code returns after that you will obviously have to investigate further.
Good luck.
There’s a very good chance the raised idle speed and the latest CEL / FF44 are related, especially if you have a vacuum leak.
Check every vacuum pipe and connection on and around the inlet manifold really carefully for splits and perishing. You could also try spraying a little brake cleaner around any connections to see if you can see it being sucked in, or listen for a change in engine note.
Quite a few members on JL have had the FF44 and CEL at some point, myself included. With some it’s been very intermittent and may only appear every few weeks or even months of driving. With others it’s been ever present from the moment the car is started until the cause was found and rectified. The oxy sensor is quite long lived but they can fail and wander out of tolerance, but it might help if you read some of the previous posts about ff44 and the causes and cures other members have had.
Check the big bellows clamps going to the throttle body, make sure you didn’t get a fold or pinch in the rubber bellows, it’s easy to mess up one of those joins especially at the plastic elbow.