It will start, but dies when I try to increase speed.

tell what it does in drive. (selector)
how fast in drive,? MPH 5 ,10 ,20? what?
is the throttle pedal dead. RPM cannot be raised right foot in drive.?
or yuou race fast the engine, right foot but speed does not increase?
or speed does increase fast and RPM fast but transmission fails to go to 2nd gear.?
scan the car is step one,
is check engine lamp on ,? idle or moving

Change air filter and clean throttle body this should increase your rpm preventing the car from shutting down

Hello, I might help a little . It sounds like the accelerator pump is not working inside of the carburetor . The coolant leak could be just a loose hose clamp. Try to adjust the idle speed screw to increase the idle speed. Good luck.

Try increasing idle speed or tweek mixture

I have seen this problem before and the cause could be TCC Staying in Lock-up or an Electrical Issue within the Engine itself or a Fuel Delivery Issue.

If the Transmission TCC is the issue, try driving at slower speeds (below 30 and come to a stop, does it Shut off then? Increase Speed by 10 and try again. Does it react differently once you go above 42-45 MPH?

Can you tell if the idle speed increases when the engine is cold ?
Are there any trouble codes in the computer ?

Sounds like your alternator went out or not making good connection at the battery terminals, preventing the battery from being charged. If the battery does not charge, you will use up the battery energy to maintain the vehicle running UNTIL you deplete the battery. the more accesories you have on, the faster it discharges till the point of killing your ignition on your engine. You definitely have a charging issue, more than likely, your alternator went out.

Sounds like the fuel pump is going out. Replace the filter first, as it's only $10. If that doesn't fix it, then it's probably the pump, which is $250.

There is a screw near the throttle body on the upper left corner of the engine, if you are looking at it from the bumper. This controls your idle speed. Over time this screw can move and may need re-adjustment. After turning the screw SLIGHTLY to the right, you should increase your idle speed to just over 1000 rpm. Then your problem should go away.

Check the IACV, its located at the throttle body, facing the firewall. They get junked up with carbon. Just clean it up with carb cleaner and bleed out the air from the coolant.