Check Engine Light?

My check engine light came on what do I need to check or what does this mean

I was just given a 1991 Ford Taurus as a gift. It has 165,000 miles on it. I am told by everyone that when it is up and running that it is a damn good car. My question is, if the harmonic balancer needs to be replaced would that keep the check engine light on and keep the car from passing smog? Also, how hard is it to replace the harmonic balancer?

1990 Ford Taurus 4 cyl Automatic

Car dies right after "Check Engine" light comes on & will not start again for more than an hour. The "Air Bag" light is constantly blinking. Checked everything I can think of. Temp is fine, Changed fuel filter. Can you give me any advice on what else it could be.

Engine problem
1988 Ford Taurus dontno miles

Hi, my taurus is showing a "service engine soon" sign and I wanted to know what could be wrong with it.
Also, the car kind of shook today which scared me. It was like it shivered.

[quote="confusedandworried"]Engine problem
1988 Ford Taurus dontno miles

Hi, my taurus is showing a "service engine soon" sign and I wanted to know what could be wrong with it.
Also, the car kind of shook today which scared me. It was like it shivered.

I took it to the mechanic and the machine read the code as "system too lean". Mechanic said I have to replace oxygen sensor and oxometer.(Is that what its called or oxygenerator maybe)?

The car just stops on me while am at the signal or someting and I have to restart it. Could u tell me if what the mechanic told me is correct. And how much the 2 parts should cost.?