I need help. I can cold crank my 1993 G20, it starts fine, runs fine, but after a good drive, when I'm idle, it tries to shut off "shaking". I'm also noticing a significant amount of gas usage "quickly".

I replaced the distributor cap/rotor button, and spark plugs. The wires are about (2) years old so I didn't botter to replace them.

With 160K miles, what else can I do?

Could be your MAF Sensor (Mass Air Flow) a electronic gadget in the tube between the Air filter & the Throttle Assy ..... Equally it could be your throttle position sensor .... Or & this is the least likely your Lambda probe......

All of these require a Multimeter to test & obviously the values that they should be ......... Sounds like its off down to the local garage & talk nicely to them...... These sensors are not cheap..... But some can just need recalibrating (Cleaning) ...... Pends how tech savvy your chosen spanner monkey is :)