It's so FRUSTRATING! The car starts on the button first time - every time, but either the idle decays & it stops, or if I touch the throttle the engine, makes a sucking noise & dies, release the pedal befor it dies & the revs climb back to idle, then slowly decay until it stops.
.......I take the Throttle Position Sensor off the Throttle Body.
I have a spare set of connectors, so I've made a "jump loom" so I can plug the TPS in away from the Throttle Body, with the car like this, the idle still slowly decays, but if I twist the TPS with a screwdriver the engine can be persuaded to rev quite nicely. At low settings it's a bit on - off, but a little more & it will spin up to 3000rpm & stay there just fine which considering the throttle is shut so it's running on idle bypass air seems pretty good & here's the thing, if I tweak the throttle & the TPS simultaneously - no sucking noise!
HOW CAN THIS BE??!!
Tomorrow's job is to take the sub-loom that supplies the injectors, TPS & the Idle Speed Control Valve off & remove all the loom tape, just to see if there's any bare wires or other problems inside.