Was at the stealership today checking on a warranty RO from when I purchased my truck. Asked about the 30k service price an explained that I recently changed my plugs, and told him that I used Bosch Platinum 4+'s. The advisor there said that the 3.4 wasn't designed for platinum plugs and that I should swap them out with regular NGK's or the truck will begin running rough, and that the plug system, having electronic coils in line, can't handle the platinum plugs.

I think he was feeding me a line, but confirmation is always good. Was he right? The truck does run better with the bosch plugs, and I've never heard of an engine "designed" for platinum plugs, or that one can be damaged by running platinum plugs in place of standard plugs. Big line of B.S. for the suckers that use the stealer for service in my opinion. Any thoughts about this?

 

I don't know if it's actually bad for the engine or anything, but I personally prefer NGK's or NipponDenso's. I ran the Bosch 4 prongs for a while and thought I felt more power from them, but that feeling quickly went away. I'm running ND's for over a year now and it's running great. The most experienced people on the boards I've seen over the years recommend ND's or NGK's.

My .02

 

Greetings Run from that dealer and quick. What a line the engine does not know what you have in it for spark plugs. It will try its hardest to fire what ever is in the hole. I have heard that the 4 prong plugs and even the 2 prong plugs, should not be used, because they, not necessarily wear out, but just dont work as well after 5-10 thousand miles. I have used the Bosch Platinums in my 22r for years with no problems. I did just switch to NGK with no adverse effects. The dealer is just being overly cautious and using scare tactics to sell you a new set of plugs. Use whatever you feel comfortable with

 

Just as I figured, more ways to scare the general and less savy public into purchases that aren't needed. This was done by our good buddies at John Elway Toyota, so that says it all.

I'll just keep running what I have since I'm experiencing no adverse effects with my truck and am about to go on a road trip to Illinois & Kentucky next week.

 

Platinums are just fine everywhere except forced induction engines. I've had pretty good results from both NGK and Bosch platinums, so no worries there. Currently I'm using NGK Iridiums, and I like them even better than platinums.

 

That's what I thought, even the dealer listed the Iridiums as replacement plugs for the 3.4L. I'll sitck with my Bosch until the 60k checkup unless they cause hicups in the engine or monkeys to fly out of my a$$, which ever comes first!

 

I think the Bosch +4's are overrated for the 3.4L. It runs great w/o them for one thing. Second, I've heard that the +4's burn too hot & can cause damage to your engine. I don't know if this has ever happened, but it was told to me by a couple independent part shop (not a Toyota dealership) guys so I'd rather not chance it myself. Lastly, I like copper versus platinum. They conduct better & I have to change them out more often which is good because then I have fresh plugs in there more often & I can see how the engine's running by inspecting the spark plugs when I take the old ones out. I think that's a win-win situation personally. Plus, the copper plugs are inexpensive & I know they won't cause any harm.