Will Bigger wheel give me better MPG

 

I bought it from a third party trader not main dealers!, I later had it serviced at a franchise dealer who only replaced the oil, oil filter, plugs, airfilter! I realise know that as an independant garage! that is the reason for such high service cost's!

 

Anyway have a much bigger issue going on at mo! a week monday my car developed symptons as if it has thrown a valve! i.e. stalling, hissing/ticking sound, running as if on 3 cylinders, and management lights on etc! took it to a new franchise dealer FRF Vauxhall, who after 1 week and 2 days havent looked at it because!!! "Chevrolet require to "see" the full service history before they authorise any warranty work!!!" trouble is I can't find the paper work since moving, alot of people are suggesting that they should not need to see the service proof to do warranty work and suggest they may be dragging out because it only has 1 month manufacture warranty left, and normally if a valve throws it usually may take out the valve guides, cylinder head or even piston head! anyway, they! have also suggested I call in trading standards who would issue the 3 R's to them, Repair, Replace or Refund, but i'm thinking of getting it back and plonking an 800cc engine in it so it will deliver better MPG and only cost £35 tax per year! PS I did end up putting higher walled tyres on it but havent had the chance to see how the economy is due to the engine failure!