sonata 2002 fuel filter location

[soh]

Just had fuel filter changed on my 02 Sonata by dealer (112k+ miles). Fuel filter is located inside the petrol tank with Fuel pump assembly. Access is from the trunk, or you can reach to trunk through right side rear passenger seat by folding it down. Dealer took about 20-25 minutes to change it but charged one hour labor (it looks like some tasks requiring technical skills are charged for at least 1 hour labor rate even though it takes shorter time to do it, e.g., dealer also quoted one hour to change two radiator hoses. I guess I will change them myself along with spark plugs).
My car was doing pretty good until about two/three weeks ago when engine check light came up for no apparent reason. I simply took battery negative terminal out for two minutes, and put it back. The check engine light CEL was gone. But I noticed car was not starting in first self as it use to be for last four and a half years. I also noticed a surge sometimes if car starts after cranking few times. I suspected the fuel filter was not propertly working, but after changing fuel filter, its still the same. I discover a new way though to start in first self (crank), i.e., turn the ignition on and wait for two or three senconds until a continuos voice (probably fuel pump working) stop, and a click could be heard. Then turning the self key will start the car in first try. I still have to understand why surge happens, i.e., the engine rpm suddenly jumps to 1.6 or so. May be some sensor is not working properly?

Soh