Toyota Emina ignitiontimingsolenoid fault?

Hi, I have a Toyota Emina 4WD auto which has an intermittent fault whereby the engine management light comes on and the car loses power (tho still runs) and the engine sounds very rough. The diagnostic came up as ignition faultsolenoidfuel pump. I can't get anybody to fix the thing as they are conflicting in their ideas of what needs to be done. The car has been running like this for almost a year now but is soon due for it's MOT! One garage wants to replace the fuel pump at a cost of £1,800, another said 'Scrap it' and another said it's just the solonoid which can be done without dropping the fuel pump etc. However, nobody seems to want to tackle the fault and sometimes the car runs perfectly for a couple of weeks without 'tripping out'. It aways resets itself after switching off and leaving idle for half an hour or so. Has anybody else experienced this with their Emina? Thank you so much, Julie.