I have an Isuzu Trooper 3.1 td, when first started from cold it vibrates excessively for about 5 mins after that its fine. I have changed heater plugs and changed the fuel filter. The vehicle doesn't smoke and runs very well, starting first time every time, if anybody has any ideas/solutions, I would be really greatful, my tel no 01903-763553, mob 07860-209092. Thanks Steve.