Sux slimey snails ***.

I had to change the plugs in the wifes Trailblazer. Went to local advance, got some plugs, went home, halfway through the job i realized they were too short to work. My truck battery was at advance for them to check it out. (optima red top, shitted out on me) so now i have to either put her truck back together or undo her batt and put in my truck. well, that took forever. positive cable was stuck. anyway, only plugs the store had left was the bosche plus 4's. against my better judgement, i got them at an additional 30 bucks over the other plugs. get home, install the plugs, wrap everything up, getting ready to hear and feel a smooth running engine and the damn thing won't start so, i make a few phone calls, two people both tell me what i already knew and i took them out. cleaned the stock plugs, put them back in, and bam, fires right up. smooth running as if it were brand new.

i did go get my money back, and a brand new red top on the house. needless to say, those plugs aren't worth jack crap in my book so stay as far away as you can.

 

That sucks dude. NGK all the way!

 

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Another vote for NGK. I have heard nothing but bad things about the Bosch +4s and all Bosch plugs for that matter. I put a set of the regular Bosch platinums in my dad's truck and they ran much worse than his old factory plugs. I used to work at Auto Zone and all of my managers basically told me to avoid selling them to Chevy owners if possible because they run like crap in most Chevy engines out there.

 

In the past, I always used BOSH platinums, and never could tell a difference. When I changed my factorys with the NGK's I could tell a big difference. My vote goes for NGK.

 

NGK's.

 

Yep bosch works well........in a four cylindar

 

i run NGK's in almost everything i own, but if you see the trailblazer plug it is rather long. NGK don't have a plug that fits right, or at least the part number isn't right. However, NGK does have a 10 dollar plug i can get but i am not going to pay 60 bucks for plugs. I am going to the dealership to see what the hell they have and why the autopart stores are so jacked up when selling plugs for this truck

 

It must be a application thing because the P+4s work well in other engines.

 

My brother installed them on his truck (5.3 GMC) and they sucked bigtime. He now has the $2 NGKs tr55 they work wonderfully. Then my cousin installed the bosche in his 2.4l I-4 Cirrus and they worked quite well. His steering wheel would shake at idle with the stock plugs. After he put in the +4s, the car ran much smoother .

So I guess the +4s are intended to be use on small size engines.