Bosch 4 tips or platinum plugs?

guys i need some expert opinion on 2 problems.my car has started to jerk a little bit.its a city idsi 06(manual).i mean after 5-6min of driving,just for a millisecond,it feels like the fuel is cut off or sumthing like that.its a jerk like thing.ther performance is still very nice,no starting problem nd changed the air filter just 2 days ago.


now 1st thing is i want to know wat can cause this problem.nd yes,my driver washed my cars' engine a few days ago nd the problem is since then.it was jerking alot at that time but now its reduce but still happens.all this is on cng.


but another thing can b the cause of it all too,the plugs r 55k kms used now.they r bosch 4 tip plugs.which usually hav a life of 60k kms.r these the plugs which r making the problems?


well even if this isnt due to plugs,i still want to change them nd need an opinion on wat plug shud i go for? 4tip bosch again or i shud try sum nice platinum plugs? my priorities r


1)long life


2)economy(fuel)


3)performance


i need to know if platinums r better in terms of performance too?i guy told me they are,but i think even if they r made of better quality metal,still,theres a difference.bcuz bosch has 4 tips,so 4 tip wud b better..wat do u guys think?


thanx in advance...
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