Throttle position sensor and injector pump. I'd really try the obvious and simple things like fluid level first before we get too far down the road.
But worth a visual on the TPS actuator cable. If you stand at the passenger side looking into the bonnet, about 2/3 of the way back from the front of the car you'll see the accelerator cable coming over the top of the engine. Follow that down and you'll see another metal quadrant with a cable that seems to disappear down into the bulkhead. This cable tells your gearbox some important stuff about what the engine is up to. On older 80's the inside of the cable sheath gets rusty and the cable won't slide in it any more. If you get hold of the quadrant and move it, it should snap back into place each time you let go. If it doesn't or in fact the cable is pulled out but whon't go back in then the thing is stuffed. There is no cure except a new one. Eventually it will snap. If it's like this, you'd be better to try and push it in and disconnect it so it doesn't get pulled out again. No biggie but it's a fiddly job to replace it.
The round plug SeaJay refers to is where the front and back wiring loom are joined together. They're usually pretty reliable but it's another avenue. It's a big cluster of wires and worth a wiggle after you have tried everything else.