walir

I recently changed the spark plugs on my 01 E55 at 45k miles with Bosch Platimum 4's. Since the change, the car misfires at idle. I was told by a MB mechanic that the V8 does not take well to Platimum 4's and should change them back to the factory recommended ones. Anyone else run into this?

newton22

I don't recommend the Plat 4s for M113 engines at all. Go stock or look into Denso IK16s or NGKs.

Ted Baldwin

.............also check the cable connection. This happened to me when I switched to magnecor wires. I had to go back to tock. In my case the spark plugs were not the problem.

Ted

walir

Thanks for the info... so, I guess upgrading the spark plugs from the factory recommended ones is not a good idea.

I also bought an HPS 1st gen supercharger that will be going into the car soon. I got a good deal on it and couldn't pass it up. HPS recommends not to upgrade anything else on the engine when installing their superchargers.

dleffler

walir, I put a set of + 4's in my 2001 E55 primarily because they were about $40 cheaper than the original Bosch plug. But before I made a final decision I had checked the Bosch web site and the +4's were listed as a replacement for the original Bosch plugs. I also had checked for the +4"s as a replacement for my 1974 Porsche 911 ( with a Carrera RS engine) and they were not listed so that made me think that the Bosch recommendations were based on technical reasons and not greed.

I now have 5000 miles on the +4"s with no problems what so ever! I had done a fairly accurate road test over a 94 mile route to check if there was any chnge in MPG, but it was nominally the same as before I changed the plugs which was at 128,000 miles. If any thing else I may have noticed a little more accleration during a full throttle run in 2nd gear.

The next thing I will be looking at is can I get 128,000 miles on the +4's like I did on the original plugs (NGK's)

Dan
Swartz Creek, MI