Bosch platinum 4 yuck!

lee1rbc

Registered User
I have been doing alot of reading and just tuning my car. Did the vacuum check with air compresser and a bottle of soapy water (gain 1 1/2 psi). Installed a new MAF, new plug wires, and a couple other things:rolleyes:

Anyway, the previous owner told me He had just installed new Bosch plugs so I didn't think anything of it. But after maf and plug wires I took it out on the highway to see what she had:confused: What she had was a miss!
The best way I can describe it is putting the pedal to the floor in 3rd at 2,500rpms to 3,500rpms it goes "vrummmmmup mmmmmmmup up mmmmup mmmup upmmm."

Then after a good Florida rain last week the miss was getting worse. I have thought maybe crank,cam sensor, DIS coils etc. But then I saw a post about Bosch 4 plugs and remembered thats what I have. So I bought a set of Autolight double P. And she runs without a hitch:D

Thanks guys for all Your info. My personnal guess why the Bosch platinum 4s dont work might be because of Fords wasted spark ignition system.

Basically 3 of the plugs are going to get a -spark thru the side electrode while the other three will get a + spark thru the center electrode. The plugs with the - spark will be weak because there is 4 side electrodes. Causing those plugs misfire, just a thought.
 
I'm running Motorcraft platinums. If you read up on the plugs and wires stuff on Supercoupeperformance.com, they state that Bosch is one of the worst plugs to get for that car. That's kinda funny because my 5.0 Mustang I just sold came with brand new Bosch splitfire plugs and I ditched them for Autolite platinums. It made a noticeable difference.
 
i have yet to hear of a car that runs good with bosch platnium 4's. the best plug i've found and i'm running in all my cars now is the E3 these things kick XXXXX!! all my cars run a whole lot better on them.
 
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my lx actually grenaded a bosch plat plug.... the insulator was completely gone... i've got it kicking around somewhere....
 
my lx actually grenaded a bosch plat plug.... the insulator was completely gone... i've got it kicking around somewhere....

A guy just brought one in to my work with the insulator gone. It was in a Ranger or Exploder I think. First time I ever saw a plug that bad.
 
E3

Haven't tried them in my XR7, but the E3's weren't welcome in my Mark VIII. They made it stumble off idle and throttle response in general suffered. So, needless to say, I got my money back on those. Went to the good 'ol double plats and everyone's happy.
 
I prefer NGK iridiums in the SC's everything else I run the cheap V-power (tr55) NGK plugs in. I learned about NGK's from my seadoo and they have never dissapointed me.
Alan
 
Autolites/MotorCraft for me in the cars NGK in everything else. Learned never to buy Champion after they didn't even go 10k miles so now its only the best.
 
I prefer NGK iridiums in the SC's everything else I run the cheap V-power (tr55) NGK plugs in. I learned about NGK's from my seadoo and they have never dissapointed me.
Alan

How are the Iridiums? I'm changing to TR6's for mine and been wondering about Iridium's.
 
It's generally detonation that kills the Bosch platinum plugs. The electrodes are small and get broken off by the rattle of detonation. Since detonation is a common occurrence on any supercharged application, it is always best to avoid any plug with platinum or iridium in it. These metals do not melt, so when they get broken loose they tend to get danced around the cylinder and play hell with cylinder walls.

It is better to use a plug like the standard Autolite or NGK and simply change them every 25K miles. That way you'll know what is going on in your cylinders and if one does eat a tip, the metal is soft (comparatively speaking) and will generally burn up causing little or no damage on it's way out.
 
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