Why BOSCH plugs not rrecommended

[holter95]

Who recommends AC delco products in a Ford as a factory replacement?

A bunch of shops I've dealt with (not Ford dealers though), plus a friend who's used them religiously in Explorers that have pushed 300K+ miles. Good enough for me.

I'm sure NGK makes a good plug, I used them in my old Subaru and they were great.

The plug just plain quit firing, it was completely fouled out. No damage done luckily.

 

[410Fortune]

Yikes! I would keep a close eye on that cylinder........coil pack, wires, etc........

I have used the +4's in my 2.9L and my 4.0L without a single problem, they noticably increased my ease of starting and smoothed out the idle. Good enough for me!!

Autolite's are good plugs, I am just curious as to why not Motocraft?

I run NGK in my boat, 2 stroke, but the Bosch +4's have proven to be great plugs in all teh engines I have used them in..(CRX, NISSAN 3.0L DOHC, 2.9L, 4.0L, 5.0L, VW)
and I am pretty **** about my spark plugs.......

 

[pumaacoma]

I was also tuning up my 91 due to rough idle and missing. At first I ruled out the plugs because I only had 20K on them (I had Bosch +4's installed) When I pulled out the plugs I had 2 plugs (1 on each side) with shattered ceramic and almost no electrode. This was the second time this occured. I never knew it was the problem with the plug until I heard about other people having this same problem. Needless to say, I bought Autolite Double Platinums and I already have 65k on them, the vehicle runs great and the autolite plugs plugs are cheaper!