Truck Spark Plugs .....

[Oklahoma Breakdown]

So I need to replace the plugs on my truck here in a couple of weeks on my 02 GMC 4.8 Liter V-8 (Gas).

Anybody have any insight on if split fires/exotic spark plugs are worth the money? Any noticible increase in efficiency, torque or HP? I would love reccomendations too if you have them.

THanks, B

[chpthril]

IMO, go with the OEM AC Delco.

[KonaKing]

X2 go OEM. I have melted some plats down before

[Oklahoma Breakdown]

I had heard that before....that cylinder temps get too high with the split type plugs. Just thought I would check. Those things are pretty damn expensive anyway and not like my old 4.8 is going to be winning any drag races soon

[Joeprunc]

DO NOT USE BOSCH!
I'd go with some plain Jane AC Delco plugs.

[larryueckert]

well i got the news today that my h2 hummer needs a new motor # 5&7 cylinder are at 78 psi why all the rest read 160 to 180 psi i just replaced the cat converters and now this it is a 2003 h2 with 49000 miles on it and i need a new engine and my waranty is up so i dont know what to do maybe call gm and tell them it should have not went out with this many miles on it i need advice please help thank larry

[chpthril]

well i got the news today that my h2 hummer needs a new motor # 5&7 cylinder are at 78 psi why all the rest read 160 to 180 psi i just replaced the cat converters and now this it is a 2003 h2 with 49000 miles on it and i need a new engine and my waranty is up so i dont know what to do maybe call gm and tell them it should have not went out with this many miles on it i need advice please help thank larry

5 & 7 are next to each other, sounds like a leaking head gasket between the cylinders. Did the tech do a cylinder leak-down test to determine WHERE the compression is going? It's actually a far better test then just a compression test, and will pin point the cause of the leak, where a compression test just tells us which cylinder(s) need further investigation.

[Oklahoma Breakdown]

What size are those engines? I havent heard of many GM blocks blowing gaskets that early. Sucks!

[KonaKing]

I think that is the 6.0 in there right? Thats a bummer. I would look at a lot of other possibilities before a new motor. Heads, valves, gaskets ... good luck.

[22VROBERT]

Stick with AC Delco plugs, GM engines do not like any plugs other than Delco plugs. GM pn#12621258, Delco pn#41-110 (IRIDIUM)

[Jason B]

I put the 4 prong exotic something or other in my Tundra. They were spendy--about 10 or 12 bones apiece--I forget, it's been a while.

No joke, my mileage went up 40%!!!!!!!!!!! I went from 10 to 14 doing the exact same driving. (yes, I save reciepts and calculate it, I'm a dork)
I will never run anything else. HUGE improvement in the power also. To be fair though, the replaced set had about 100k miles on them.

[TeamAllen]

Jason, I think your improvement is from the change from a worn out set. I have an 03 Tundra V8, an 04 Tundra V6 and an 04 Sequoia. 14.6 is the average foe the V8. About 16 mpg on the V6.

I use only NGK spark Plugs. I would even put them in the GMC. In fact, I put them in the boat too.

[Joeprunc]

X2 on NGK or Denso plugs in Toyotas'.

[ajholt7]

Buy a diesel and forget it. J/K. I have always had good luck with oem. If it was running good put back in whatever you take out.

[larryueckert]

ok so i tell the gm dealer to put my hummer back together because i'm not forking out 6000 bucks so they do ..i pick it up it dies in the parking lot ..i start it back up and dies again ..i almost started crying started it back up and started down the highway it started to run a little better....drove 2 miles or so and it never died ...took to my buddies shop he checked the compression every cylinder was running just fine.......called the gm dealer they never ran the hummer after putting the cat converters on the went by the sound of the engine and the dinostic test ...once i ran it for miles it cleared the cylinders out got oil back to #5#7 so long story short my hummer run great and the gm dealer is on my sh!t list