My 2002 accent, started running rough and using a lot of fuel the last month or so.setting off MIL,put my code reader on it, and came up with po301&po304 cyl 1 & 4 misfire. tested coil & wires , all ok. then checked sparkplugs that i had installed 3 months previous. center electrodes were completely gone on the #1 & 4 plugs," Bosch platinum sparkplugs". I have already sent a letter to bosch to hear their take on this. was wondering if any one else has experienced this? i would be interested to know. B

 

Seems very strange that those electrodes are gone. Are you absolutely sure that they where actually changed?
Personally I wouldn't run the Bosch Plats in that car. (just use whatever Hyundai calls for)

 

yes it is very strange, and yes i put the plugs in myself. put some ngk,s in now it runs fine!

 

Put Bosch plus 4 plugs on my 99 Accent and 04 Elantra with no problems at all. Great plugs. Maybe the place you got them from gave you the wrong plugs for your car.

 

may I ask the part number on NGK sparkplugs?

 

don't waste your money on 'extra prongs' on the spark plugs. use the regular single elecrode. as for bosch +4's i have had problems with them in vehicles that use a waste spark ignition (one coil pack fires 2 cylinders) because the center electrode on the 'ground side' fires from one of the 4 electrodes to the center. it's sorta like trying to land ahelicopter in a hurricane. it ain't always easy.

anyway. po301 = cylinder #1 misfire, so po302 = cyl #2, all the way up to whater # of cylinders there are. po300 is random misfire.

looks like you have it figured out with the fresh plugs, though.

df