[coachman]

Originally Posted by tomdigym

Drove home from Biggar last week again the lorry drove faultless, again it was as slow as a fortnight (40mph).This has been ongoing for the last 3yrs everybody has an opinion i.e dirty filter/fuel, faulty pump,injectors,blocked fuel line etc etc,I was never convinced that it was any of that so today l checked if l was getting full throttle as it happens someone had screwed in the throttle stop(difficult to see with the air cleaner on).I screwed this out only to discover it was still not full on but better,I then checked the linkage and found it to be worn,bent & wobbly.I stripped it off straightened the rods washered up any play and just a general going over,refitted it went a short run 55MPH ya dancer.So next time your looking for they lost horses check your throttle stops & linkages etc before spending fortunes on anything else.
Cheers Tommy

Also don't forget to check the air filter and any pipework associated with getting air into the engine as well. From my experience people often forget that all engines need air just as much as they fuel.