1992 Chevrolet Corsica Rough Idling and Speedometer Issues

When the car is cool open the radiator cap and look for thick brown stuff in the radiator. Its oil going into the coolant system through the upper intake gasket which causes running problems. Also if you've not done it a tune up is a good place to start

And the gauges are probably going bad as well and are available at local parts stores

What kind of gauge would I need to buy?

There is no oil in the coolant, it just had a tune up apparently before I bought it, but we have noticed that it does this when the car is cold, (or first time driving that day) if the car is warm or has been driven and stop through out the day it seems to run fine.
I have also noticed a exhaust type smell when I start the car or it is idling rough at a stop light, I know that it needs the muffler replaced, but wasn't to sure if that smell was a sign as to why it is running and idling rough.

This is good. But on the other hand it makes it hard for me to say for sure whats going on with the car now. It could be anything from a failing catalytic converter to an ECM or coolant temp sensor problem. Drive it this way a little while longer as there doesn't appear to be any danger of mechanical damage. It should most definitely set a code so we can go further

I managed to get a code the other day off of my code reader and it was code 44.

Ok. Now we are getting somewhere. That's a code for lean exhaust. This is most often caused by a vacuum leak. Crank the engine up and spray carb cleaner spray around the top of the motor and listen for the rpms to rise slightly. Thatll show you your vacuum leak if you have one. Its usually a hose or plastic fitting that's unplugged or broken. The other thing thatll cause a lean exhaust is lack of fuel, and it could be due to the coolant temp sender making the ECM lean out the fuel when the car is cold and it should be richer.

My husband said that he went through everything checking for vacuum leaks and never found any, so we will try replacing the Engine Coolant Temperature Sensor and see if that makes a difference, I will post later about it.

Ok good. As for the gauge, youd be replacing the whole cluster if it was determined that it was bad