Hey guys this is my first car and I've been doing my own repairs and maintenance to save money but this problem might be too big. I've taken it to a mechanic last week for a quick diagnosis / check engine reading. I am dropping it off tomorrow for the day for a full diagnostics but I'm always sketched out about mechanics and would like some advice.

Squeaking noise coming from the timing belt area. This usually happens after long drives like on a freeway or on hot days. I first thought it was the auxiliary belt but it still made the noise when it was completely off. Can it be the timing belt or some rollers that are loose?
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Engine rpm revving / engine surging often happens when in put it into park or when I am slowing down. It has died on me two times recently when applying the breaks and slowing down. Mechanic said there is a leak and the psi is too low.
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Headlights also surge along with the engine.


Engine codes

PO171 BANK 1 LEAN

PO191 FUEL RAIL SENSOR

PO190 FUEL PSI SIG FAULT