I've heard the same thing man. In my 850, I use the Bosch Platinum +2's because I've noticed the +4's actually make me lose performance, and don't last as long.
I tried them on my car (iridium) took them off cause they didnt perform well compared to the stock plugs. I kept getting check engine light. I really saw no difference in the performance with those plugs...In my Opionion I dont think they are worth the money.. I can sell you my set for 1/4 the price only gone like 300 miles..
I am using denso iridium plugs, and I think they perform a little better than the stock plugs in overall characteristics. The idle was smooth, and tiny increase in mpg. And the thing is that these replaced the stock plugs which had only been on for 3 months. (so its not just those increases because of new plugs)
Pete
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
SwedeSpeed - Volvo Performance Forum
3.9M posts
157K members
Since 2000
A forum community dedicated to Volvo owners and enthusiasts. Come join the discussion about performance, builds, modifications, classifieds, troubleshooting, maintenance, new releases, and more!