1991 Toyota Tercel

Hello,

I am trying to help a neighbor (elderly) out.
She has a 1991 Toyota Tercel LE with 74,500 with a 1.4 liter engine?.
It won't pass marta emissions.
Her tags have expired, so I just can't jump in it and run it to a mechanic.

The car starts fine, it idles fine, put it into gear and it idles rough, but does not die.
The car had new plugs put in it 19 months ago (4000 miles ago) and a new air filter, it looks fine. Oil was changed at that time as well. I found this out by looking thru all her paperwork.

I checked the oil, and it has a "gas" smell to it. I took off the oil fill cap as well and it has a "gas" smell too. The oil looked fine and clean!

Car does not smoke on start-up or while it is running.
BUT, I noticed the tail-pipe has a large amount of Black-sooty stuff on the inside of tail-pipe, I mean thick!

So before I start replacing one item at a time, do you guys have a idea of where to start.

I am not that mechanically inclined, and thought she may need a new air-filter or new plugs, but they both looked almost like new.

I know you probably won't be able to help me because I don't have the "codes" or anything.

But any help beats no help.

Regards,
Jack