ive been using the bosch 4 spark plugs for a few mopnths now and latly im having a prob with the number 4 cylinder plug backing out and throwing the engine light any idea why its doing this?

Put AC delco's in. I've only had best luck with factory plugs..

Yeah, my friend had problems with bosch. They did the same stuff.

I'd stick with the factory plugs. +4 platinums are a bit overkill, unless you plan to run high octane fuel and tune the engine accordingly. Besides, why waste more money on plugs than necessary.

Yeah, my friend had problems with bosch. They did the same stuff.

maybe you can try use another brand, like NGK. i have been using it and so far so good.

http://www.gmpartshouse.com/genuine-gm-parts.jpghttp://profile.ak.fbcdn.net/hprofile-ak-snc4/hs622.ash1/27523_118885218140666_2422_q.jpghttp://www.gmpartshouse.com/genuine-gm-parts.jpghttp://profile.ak.fbcdn.net/hprofile-ak-snc4/hs622.ash1/27523_118885218140666_2422_q.jpghttp://www.gmpartshouse.com/genuine-gm-parts.jpg

http://www.musclecarsforever.com/images/old_ads/1972_GTO_AC_SparkPlug.jpg

I know this thread is slightly old but what would be the best performance spark plugs to get?

Yeah, my friend had problems with bosch. They did the same stuff.

I also had the same issue with bosch. I changed them to a different brand

Bosch is best for European cars only.
For American cars, use Delco or NGK. They were designed to run on these plugs and will give you the least problem.

Alright thanks mrslcom