Hello, I have a 102,000 miles 2.0Dti. It has just begun an intermittent fault, when at low throttle the engine will almost stall and lose almost all power. It will automatically rev up to around 1200 RPM and then fall back to almost stall and then repeat. It responds to throttle pedal and revs up cleanly. No black smoke at idle or on heavy load or high speed. Starts, cruises and accelerates perfectly, even 80MPH up motorway hill with no issues.
I had fault codes checked - none present which surprised technician.
I pulled off loom to MAF sensor when it was misbehaving today (whilst running but stationary), fault cleared. So I replaced MAF with new BOSCH unit. Sadly the fault is still with me and still intermittent.
Problem is becoming more frequent and more serious - started about 10 days ago.
I am looking for vacuum leaks but pipes/unions all seem ok.The 3 control valves that the vacuum pipes lead to all seem to bleed vacuum when engine off, I presume this is normal(?) All three actuators operate smoothly and easily.
Any suggestions welcomed.
Thank you. Mat