Birdman

Just to add to this, the MSD units as well as some others send multiple pulses during the ignition stage rather than just a single pulse, resulting in a more complete burn of the air/fuel mix. In the more intelligent units, the number of pulses sent is determined by the amount of resistance measured between the gap during the first pulse. Higher measured resistance results in more pulses in order to insure that the additional fuel in the cylinder gets burned more completely.

bike4miles

Yea, they arnt' worth a damn in a Toyoat. Get some new NGKs and be done with it.

firemedic

Didn't read all the replys, but I had some Bosch +4 in my 5 series BMW, they were fine, until the car wouldn't run smoothly, I checked the plugs first and found that one of the plugs "lost" all 4 electrodes . I replaced with another brand and never had a re-occurence. I'll never use the +4s anymore.

HaveBlue

A set of copper NGKs will be half the price of the Bosch +4s. I've run the Bosch plugs on my Corolla and the 4Runner. They're junk. They caused the Corolla to miss excessively and the 4Runner to lose .6 MPG. Kinda funny considering they promise an increase in mileage.

Bigkahuna808

They sucked I had them for 15,000 miles and its a waste of money. Im running the NGKs that are stock and they run better

Vtec_Killer

Never had luck with the Bosch 4 in ANY of my vehicles. I use Bosch Plat in my Volvo, NGK-R(2 ranges colder than stock) in my Audi S4, NGK-R(2 ranges colder than stock) in my Eclipse GS-T, and will put NGKs in my Runner here soon.

X-AWDriver

Platinum is great for longevity but really isn't a good conductor of electricity but it's "good enough" for standard applications.

Fizboy

I have been running platinum 4's in my 3 slow since I put a new engine in it. That was about 30K miles ago. I haven't had any problem with them and every time I take them out to check them and see how the engine is running they are clean and in great shape. As for gas mileage I'm getting the same 18mpg running 33X10.50 as I was running 31X10.50, but that could be from other mods on the engine.

This thread is inducing curiosity. I have a set of platinum 2' and a set of Toyota plugs. I think I will test to see which gets me best mpg and overall performance and post my findings here.

hydrochskier

The real technical reason why Bosch Platinum or any platinum plugs are not good for the 4runner or Tacoma 5vzfe engine is that on the 5vzfe engine the ignition type is called a wasted spark ignition and the way it works is the 3 coils above the passenger side of the engine spark the plug below it and the opposing plug on the other side of the engine. One plug sparks on the compression stroke and the other on exhaust stroke hence "wasted spark". Anyway in order to spark 2 plugs simultaneously the coil sparks the plugs through a circuit where the current passes in a loop from the center electrode to the outer 2 prongs (4 for some Bosch plugs) through the engine to the opposing plug's outer prongs to the center electrode then back to the coil completing the circuit. This is a great electrical system except the sparkplugs used must be able to handle the spark jumping the other direction for the driver side of the engine. When I first bought my 4runner it had a rough idle and terrible acceleration so I checked the plugs and found this on the passenger side of the engine . The plugs looked fine but then I pulled out the plugs on the driver side and found this . As you can see the platinum is gone due to the spark jumping the opposite direction (the Bosch platinum 4 is the same as the pic but with 2 more prongs). Now I don't know what the direction of the current is to determine weather the platinum is being zapped out of the ceramic surrounding or if it being welded to the outer prongs like an arc welder. All I know is that the stock Denso or NGK plugs are designed to handle this kind of application because they don't have platinum. Platinum is too soft of a metal to handle the backwards spark.