First noticed last year after long drive of 300 miles straight. Burnt
out one spark plug and car bucked like a pony running on 3.
Had one coil replaced and changed the spark plugs. Fixed.
Now 1 year later, I burn out a plug every month or so after a long
drive, or one uphill. I feel like it has something to do with the
amount of fuel the plugs are getting. It is stick shift and when the
timing between the brake and the clutch is difficult, like going up a
steap incline in snow or driving in real racing traffic in NYC then the
spark plug burns out (ends burn then break off) under the coil packs
only.
***This car has on the engine a sticker requesting only double grounded
spark plugs (two arms at end) which I noticed a few months back. The
double plug gives the car a lot more power but is burning out quite
quickly. Car has 96K. Problems started at 70K.
Should I try the new Bosch 4 grounded plug?
If it is a fuel mixture problem, how does one adjust the amount of fuel
going to the plugs?

Thanks