The topic of spark plugs, like most everything car related, seems very controversal. Why, aside from higher cost, does most everyone HATE Bosch 4's? I've used them before, and thought they ran/fired great. In a car like our 3rd gens, a plug like this makes sense, since a plug change can be a little tight at times. Does anyone have any hard, cold facts/eveidence that these are, in fact, a bad plug choice, and they REDUCE performance? I'm aware that Delcos seem to be the plug of choice on this board, but does it stand to reason that a company like Bosch, that makes quality injectors, oxygen sensors, etc, the very brands that come in our 3rd gens stock, would use inferior spark plug technology/engineering, just for the heck of it? Comments, please.

 

I ran Bosch platinum plugs in my car once.....once, never again.
With less than 500 miles on a spark plug change I was getting bad hesitation at WOT and a horrible idle. Since I had just changed plugs it didn't occur to me that they might be the problem, so I took the car to the dealer where they hooked it to the scope and said the plugs were fouled. I had them pull a plug and sure enough it was black and wet.
The service manager said they never use bosch plugs because they run too cold for GM vehicles.

 

some like them some dont..

i like a/c delco plugs..

 

The plat. 4 plugs are a gimmic plug... there is no way u can get 4 sparks... they just are really expensive.. $6 for plug... A/C's will do a u better for a lower cost.... u will get guys sayin that the +4 are good, and some say there crap.... there really a waste of money.... I work at a parts store... they really dont do shat for performance.... if ur tryin to get horsepower from "super" plugs...ur in the same catagory as thoes that put stickers on there car for "power"

 

Junk.

Electricity can only follow one path at a time now matter what it looks like to the human eye. The Bosch ends up giving you more sparks (never more than 1 at a time), but they are smaller and weaker sparks compared to the normal plugs which give you a much larger and more full spark.