My wife has just sold her much-loved 1996 Jeep Grand Cherokee and bought a newer one, a 2000 Grand Cherokee 4-litre petrol which has only 38,000 miles. It’s been a Chelsea tractor and well looked after. We realize it’s a gas-guzzler but we go ballooning and sometimes have to tow, and also we use it locally in Brighton when there is snow to deliver Meals on Wheels. The comfort is great and at £2600 it compensates the running costs, we hope. The question is, can we help improve on the fuel economy? The old Jeep had four 225/70 R16 Pirelli Scorpions. The new Jeep has 245/70 R16 Continental Cross Contacts on the front and Goodyear Wranglers on the back, all in new condition. Can this engine be remapped for fuel economy?