spark plugs broke in situ

[AndyLFC67]

Hi folks
Ive got a 2000 1.2 16v Corsa B which had been running really well until around 2wks ago when the idle started getting slightly erratic.
I took the 6 month old Bosch super 4 plugs out thismorning to have a look at the colour as I suspected a weak mixture.
However, to my horror the last 2 plugs on the right had no prongs left on them!!!!! Put the old plugs back in and running really well again but how has this happened and, more worryingly, will the prongs stil be in the cylinders causing damage? They were the correct plugs for the engine according to Halfords. Cheers,

Andy

[johnny]

more than likely just bad plugs that were damaged before being fitted, they will still be floating about the engine somewhere either in a gallery just waiting to cause a block, sitting in the sump or still in the chambers

first thing to do is pull the sump and hope there there, if you or any previous owner fitted a magnetic sump plug then it may only be a matter of removing it otherwise to find them you have to strip the engine

or you could pray to your mystical person of choice that they get safely mashed up and cause little damage

[AndyLFC67]

Cheers Johnny
I'll pray to every known 1 if it helps.
Could the bits get into the engine from the cylinders? Would they fit past the valve stems? Had a poke round with a magnetic screwdriver and theyre not in the cylinders anyway. Was hoping they may have gone out of the exhaust valves. Andy

[johnny]

they can very easily get broken up by the piston and then get anywhere unfortunately, but they could have been pushed out the exhaust ports aswel