So... got the car looked at.
I was dissapointed, because other than just interpreting th code (P0420) and telling me that it means I need to replaces the Catalytic Converter, the mechanic did not perform any actual checks to see if that is the real problem.
So that question still remains unanswered.
However, the wierd, electric whiering noise he said is the Alternator AND its pulley, both needing to be replaced.
As my request, he checked the timing belt. Its never been replaced, and the car is at 110K
so as far as I know its 20K over due...
With the belt he recommended replacing the water pump, the alternator belt, the A/C belt, and changing the coolant (which also probably has not been done in a long time).
He gave me prices for parts, and labor seperately:
CAT converter - $589, not from Nissan, as they wanted a lot more for it.
Gaskets - $32
Alternator - $369
Pulley - $38
Water Pump - $78.90
Timing Belt - $48.60
Alt. Belt - $28.44
A/C Belt - $21.60
Coolant - $18.50
All but the CAT converter are from Nissan.
Labor for all of this put together is $660
All together comming to a little over $1900
So...... I'm desperately asking for help. Though much of this is my friend's neglecting maintenance over the years, the fact remains she does not have a lot of money, and that's an understatement. If there's somebody out there who can guide me, step by step, on what to check in the car myself to make sure the problems are indeed real, and then where to get parts for a good price, and then how to put them in, that would be exceptionaly great! Even more so, if there's anyone with a good heart and good knowledge in the southern NJ area, or the philadelphia area, or even a little farther than that in any direction... who's willing to look at the car and diagnose it with me, I'd be eternally greatful and would compensate you for your time.
I need solid, concrete knowledge and guidance please.
Please contact me here AND at my e-mail address : firstname.lastname@example.org
(the redunduncy just to make sure I get it).