Engine idles rough and makes growling noise most noticeable on the front of the engine?

Hello Joe, you are right it might be a vacuum leak, this 2014 Nissan Versa SV engine is equipped with a tachometer and when the car is idling at the red traffic light in the Drive position the tachometer registers an idle speed of just 500 RPM or just 500 revolutions per minute and it barely idles and barely keeps the engine from stalling out, at idle in Park the tachometer registers an idle speed between 500 RPMs and 600 RPMs and I think that the normal idle RPM in Park should be 750 RPMs, I said in my original post that I would download the photo of a removed engine but the laptop computer refused to download the picture, this time I will try to download the photo of an engine that is still in the car, Wow this time the photo downloaded successfully, so I know that in the front side of the engine right above the intake and exhaust variable valve timing solenoids there is a vacuum hose that goes from the valve cover to the PCV valve, but I see vacuum hoses next to the electronic gas pedal which I don't recognize and I don't know what they are there for, any help is greatly appreciated, thank you Joe.

The reason the engine in the picture is looking brand new is because it's not our engine, I don't know how to use the laptop computer's webcam (web camera) which is located right on top of the computer screen, I don't know how to use the computer webcam to take a live photo of our engine because I am computer illiterate, instead this photo came from the bing images search website where I typed 2014 Nissan Versa SV engine and this engine photo came from a car dealership website and I am sure that they polish and shine the engine so they can sell the car, excuse me Sir Joe (JacobandNickolas), but if our engine barely idles at 500 RPM when we stop at the red traffic light then if I mess or fool with any vacuum hoses or any vacuum lines won't that further (farther) dilute the already lean air-fuel mixture or air-fuel ratio coming out of the fuel injector electromagnetic coils, needle valve armatures, and needle valves and out of the electric fuel pump's electromagnetic poles, armature, impeller, rotor, turbine pumping element, and cause stalling at stoplights? Also I notice that there is no fuel return line and no fuel pressure regulator in this vehicle like the ones found in 1990s model new cars back in the 1990s and also from the electric fuel pump module picture in the Advance Auto Parts website I notice that the electric fuel pump module has no strainer underneath it, are fuel pressure regulator, fuel filter, and fuel pump strainer internally located in the thick plastic cylindrical electric fuel pump module? I was just curious, thank you Joe (JacobandNickolas)

Wow, your sons have a very good father, a professional auto mechanic, I wish my father was an auto mechanic and then I wouldn't just blather listing auto parts like the parts of a fuel injector and fuel pump module I listed above, if my father had been an auto mechanic then I might have been able to actually service auto parts and unbolt them and put them back on bolting them with a torque wrench, now the bolts that hold auto parts together their bolts are too tight for me and I can't loosen them because I have no mechanical expertise because my father wasn't a mechanic he was just illiterate who spelled take as tak and wrong as ron, Sir Joe back in the early 2010s we had a 1995 Ford Aerostar minivan with the 3 liter V-6 engine and its engine was idling with noise, then I took it to the Gainesville Florida Pep Boys and they did a tune-up and while trying to access its spark plugs they broke some vacuum hoses or vacuum lines and the air fuel mixture got lean and it was idling rough but the engine noise quieted down and before the tune-up the oil smelled like gasoline and the spark plugs Pep Boys removed were very sooty, so I don't know if the idle in the 2014 Nissan Versa SV returns to a normal higher speed I don't know if a higher idle speed will dilute the oil like it had happened with the domestic minivan, but the Ford Aerostar minivan had a lot of breakdowns, it had too many breakdowns like a discharging alternator (once again I can only list the parts but I can't work on too tight bolts and alternator parts are pulley, internal alternator fan, bearings, rotor electromagnetic poles, stator core, stator windings, rectifier, positive and negative diodes, internal voltage regulator), badly leaking heater hoses that weren't available at auto parts stores, leaking water pump, starter motor with a corroded terminal and a new starter motor being sold with an attached terminal cable on it (parts are brushes, commutator, electromagnetic poles, armature core, armature windings, pinion gear, solenoid plunger lever and plunger return spring, water pump parts are pulley, bearings, shaft, impeller, mounting gasket, weep hole, once again I can only list parts but I can't untighten too tight bolts because my father was illiterate), while our 10-year-old Nissan Versa SV went for 100,000 miles with just the synthetic oil changes, a couple of batteries, and an electric cooling fan but still has the original alternator, water pump, radiator hoses, radiator, I am sorry for having been so wordy and loquacious Sir Joe but I have low self-esteem and so I need to learn about and list auto parts I learned from James Duffy's auto engines book to boost my self-esteem because my father was illiterate and that's why I developed low self-esteem, but I am scared about the idle speed going higher because I fear oil dilution and engine dieseling or run-on, thank you Joe and you are a very good father and you taught your sons very valuable skills.

Thank you for responding so promptly Joe. You mentioned a spark plug and our 2014 Nissan Versa SV is almost 100,000 miles and we have it since it was 3 years old and 7,000 miles and we have never had gotten a tune-up on it, I notice that the intake manifold and air only throttle body and air intake hose are blocking access to the four direct distributor less ignition coils and to the spark plugs so it will take an awfully lot of labor to access coils and spark plugs, I saw internet photos of a newer 2021 Nissan Versa engine and I noticed that in 2021 Nissan has cleaned up its act and it no longer places the intake manifold on top of the engine and all it takes to access the spark plugs on the 2021 model is the ignition coil electrical connectors and ignition coil mounting bolts and just one of the four ignition coils has a vacuum hose on top of it but not the whole intake manifold, do you have any idea how much the tune-up on a 2014 Nissan Versa SV might cost? And I have seen auto mechanics use power tools or air impact wrenches to loosen tight part bolts, thank you Joe

I read on the internet that if the 2014 Nissan Versa SV electronic gas pedal is disconnected then its idle speed needs to be reprogrammed upon reconnecting it, I don't have the expertise or equipment to program or reprogram engine related electronics, just a simple question, I know that the online auto owner's guide recommends spark plug replacement on a 2014 Nissan Versa SV at 100,000 miles and we are currently at 98,000 miles which I had rounded it off to 100,000 miles in earlier posts, the question is that if we don't put too many miles on the vehicle over time is there a time limit to change the spark plugs if the time comes before the mileage? I am asking because my parents only put one mile a day on our 2014 Nissan Versa SV, thank you Joe