[Laird Scooby]

The most likely cause is a split in or a loose hose between the MAF and the throttle body. This will cause exactly the symptoms you're getting.

As for your tests on the TPS, what you've got seems right as it's not a sensor but two switches, one for idle and the other for full throttle.

However, you've told us the biggest fault of all. The alternator isn't giving an output and the battery is flat. Either of those will cause erratic running and can manifest itself in a number of ways.

First thing to do is to sort the alternator, you won't get any solid conclusions on the injection with a FUBAR alternator.

Does the charge warning light come one with the key at position 2? It could be something as simple as the bulb, to prove this find the thin red wire (NOT the thick one!) on the back of the alternator, unplug it and use a piece of wire to jump it to a good earth. With the key at position 2, does the charge warning light work? If not and the other warning lights come on (bulb failure, low washer, ABS if fitted and a few others) then it suggests the bulb has failed. If the bulb works but not when the red wire is reconnected to the alternator then the voltage regulator on the back of the alternator is suspect but there could be other problems in the alternator.

The choice of the next step depends very much what you find when you investigate the alternator. There are no short cuts, you need to fix the charging problem first. Don't forget to check the belt is tight!