1992 Cadillac 4.9 ltr - Runs rough, No power - Please help

I am trying to fix my mothers 1992 Cadillac with the 4.9 liter motor. It has 102K. The only problem she said was that the car will hesitate and had no power some days, She said this problem would come and go. I have drove it all last week no problem, then it happened to me today. Now it seems like the problem is here to stay.

Here is what I know.
I thought it smelled like it was running rich.
The EGR had a broken vacuum line the I fixed that(I don’t think that anything to do with it).
Gas Mileage dropped from 22 mpg - 13 mpg (computer reading)
I checked the plug and wires - newer ac delco platinum plugs and new wires(everything still looks good)
Wiped out throttle body
Vacuum hoses looked good
A/C and Cruise Control stopped working when this problem started
Check engine light just came on (obd-1) - have not read yet

I am not sure what to do next? I am think computer or Mass Air Sensor.
Ideas please, I do not just want to pour money into this think.



Update - I am not sure if anyone read this but I check a second fuse box under the passenger side I had a blown 15 amp fuse. The car is seems mostly back to normal. I can do not know what else is on the circuit be the car seem to run rough or under powered if I do not have my foot in it? I don’t know if is shifting early or some thing?

What is on that fuse that you DO know about? Its got a label someplace.

Did you even pull the error codes? Here is a handy guide for doing do on OBD-I:

Anybody know anything about a - Viscous Converter Clutch Brake Switch ?

Yes I checked the codes e40 just found code ff48 - i believe this ac ref. code

A/C compressor Control Relay
Viscous Converter Clutch Brake Switch <<<-Don’t know how or where to check?
EGR Solenoid
Vaper Cannister Purge Solenoid
Power Steering Pressure Switch

It is almost like when valves would float or chatter like when someone used low octane or bad gas on older cars?

It was bad gas - When I bought it, it probably had low octane. Filled up with the good stuff and lucas wiped down throttle body runs great. only problem ac compressor is short cyleing?