1997 Nissan Maxima starting Trouble

[spatki1]

I have 1997 Nissan Maxima, having starting troble since last 2 months.
I replaced bad starter with remanufactured starter, after 15-20 days my car could not start, i took starter to dealer again he tested starter it was good but i insisted to replace with another brand, he replaced for me with another brand.

After Installing starter it started making big noise & do not start smoothly as before, my friend who si mechanic told its not starter its something in egine, or fule system which does not give enough power or gas to start engin smoothly, it could be fuel pump, fuel injection system or Timing belt or some sensor in engine....I took to one mechanic but he told it could be flywheel problem. My friend told me if it is fly wheel problem then will be diffrent noise like grinding noise ... it must be something within engine...need machines to test & trobleshhot problems.

i asked 2-3 mechanics but they are also not sure whats the problem & they told mee they will charge me 2-3 hr labour just to trobleshoot the problem

I have regular servicing of car, regular oil change , last year only replaced Spark plugs orignal from Nissan , changed belts, Starter recently , always have Mobile 89 Octane Ggas ... dont understand whats wrong with car.

Today in cold weather it was trying hard to start but could not start at last...the noise is really rattling & feel like whole engine is shaking...

Pl help me trobleshoot this problem ASAP...

Thanks

Spatki