I need your help please.
Wednesday: Within 10 minutes (5 or 6 miles) of leaving home and having been on the A34 for a couple of miles, "MCSF error ; visit dealer etc" message appears and no throttle response. Water temperature normal. Dipped the clutch and pulled over, engine idling smoothly and no misfire. Switched off, checked engine bay and nothing obvious. Engine started ok and started driving again but was having to press throttle pedal half way to floor before it responded. Limited power thereafter and couldn't accelerate beyond about 60 mph. Pulled over again, switched engine off and left it for about 10 minutes. Had a good scout around in engine bay checking electrical connections and intake hose etc but nothing obvious. Restarted engine, throttle response and engine power restored and continued my journey to work. Engine warning symbol displayed throughout this time.
Left work at the end of the day and similar chain of events occurred. Switching off engine and leaving for a 10 minutes before restarting the engine seems to reset the fault although the engine check symbol remains displayed. Took the car to Palmer and Philips in Oxford for diagnostics. Fault in throttle circuit recorded, I think the fault code was P0020 but I couldn't really see well enough because of reflections. Fault code was cleared and I went on my merry way after discussing possible causes. I followed their advice and cleaned throttle body that evening..........some oil deposits were present. Intake hose appears in good condition.
Thursday: 52 mile round trip to work, everything fine and dandy.
Thursday evening, went out and within a mile, MCSF and no throttle response again. Checked engine and found that the oil breather on the front bank of cylinders was loose so potentially creating an air leak. Applied some sealant and tightened screw. Left it for the night. Checked battery voltage as 12.7 volts with ignition off.
This morning: set off for work and within a hundred yards, no throttle response. Switch off for a few minutes, restart and all is ok. 10 minutes later, whilst joining A34, no throttle response and visit dealer message again.
I've disconnected battery to perform a full ECU reset and will do a throttle calibration cycle when reconnected. What else can I check, any ideas would be much appreciated ?
Although the car has been standing for 6 to 8 months, the battery was regularly charged and the engine fired up once a month or so. Following an oil and filter change, it flew through the MOT a couple of weekends back and Wednesday was the time I drove it since the MOT.
Update: full ECU reset (battery disconnected for 1 hr or more) and Throttle body reset has made no difference. As soon as the engine is started, the "MCSF visit dealer" message is displayed.