I have checked live data and all looked OK. Yesterday my lad and I were checking the operation of the egr and the butterfly choke on what you would call the throttle pipe. Both of these are vacuum operated and both worked as would be expected through the rev range of Off, Idle, 2k, 3k and 4krpm. During one of the range checks whilst descending the range and whilst at 3Krpm and holding the defect arose whereby the revs dropped to 2200rpm whilst the throttle was held at what was the 3k mark. Subsequent throttle pedal movement to full on did not have any effect on the rpm. Upon taking the foot off the pedal the engine went to idle and upon pressing the pedal it revved as if nothing had happened. We repeated this with live data on and it showed what you would expect of the engine revs produced so the Fuel Rail Pressure dropped when the rev dropped from 3k to 2200rpm. correspondingly. During this the egr and butterfly worked in harmony too.So something appears to be throttling the engine and not allowing it to increase as if it was a safety intervention or limp mode scenario!
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