been havving some trouble with my gti-6, i serviced it at around 80000 miles with the usual, oil ,oil filter,air filter and plugs (basic) service, i took out the old plugs and stupidly threw them away(as you do .....) without taking note of what they were, since then i have been getting really bad mpg (i.e 327miles to £120 worth of fuel) the car is completely standard apart from a de-cat pipe and stainless cat back system, anyone have any ideas??
i thought maybe because the exhaust it would have made it a bit more juicy but surely not that bad, If i have put the wrong plugs in it would that make it that bad, also im aware that it is running extremely rich, would this all be to do with the exhaust change or could it be more?? a lambda sensor or something more in depth, its also recently had a icv.

any help guys would be great as im spending nearly a weeks wages to to get to and from work at the moment

also can anyone tell me what iridium spark plugs to get

cheers in advance
Lee

spark plugs are not your problem.
Green Coolant sensor, Thermostat, lambda

one of those will be your issue

No the exhaust was done about a week later
Cheers lee