Hyundai Santa Fe diesel turbo acceleration hickups, hyundai

The car has serious hickups, jumping, while accelerating. While driving at even speed it does run ok, in idle also ok. The car has recently had a fuel-based engine/compartment heater installed. Might I just change the fuel filter, or what should I expect is wrong? Thanks in advance... ;)

Answer
    We don't have these vehicles here in the states, but I'll take a stab.  Since it idles smoothly and runs smoothly at speed I doubt that there is any problem with the engine or fuel system.  I would be suspicious of a broken engine mount.  When a mount is broken (could be a transmission mount, as well) it lets the engine move around under acceleration.  This can cause the linkages to the throttle, clutch, and transmission to move even though the driver is not operating them.  It will produce the same symptoms you describe.  One way to check is to look under the hood with the engine running while someone holds the brake down and operates the engine/clutch in gear.  If a mount is broken, the engine will exhibit a great deal of movement and maybe some noise.
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