Spark plugs

[Cobra]

Hi All
Replaced the OE AC plugs at 100K with the Same Stock plug
The OE looked VERY good with 100K so why change if it is not broke
do not try to fix it

Did min around 77k and yup those stock ones looked great. So stuck with OEM ACDelco Iridium spark plug. I kept hearing from everyone that is what are engines like best. I did change wire to MSD 8.5

 

[Redhoe01]

So do we need Iridiums for our trucks?

 

[TERRYCCTT]

the plug that is best for these trucks are the acdelco 41-110 i think is the number. they are iridium and were made by ngk so the ngk plugs are good. you can however use a resistor plug for more power. champion is mainly used on chrysler and lawn mowers but are ok. autolite isnt too bad but i wouldnt use them on anything i have. bosch is the worst plug known to man and ask any mechanic or tech at any shop. i have changed more bosch plugs between the day a person puts them in to about 60k miles. they never burn clean and foul quik. i use the oem plug with msd coils and wires.

 

[t_ahan]

oem plugs

when i installed msd coils the truck felt worse and after talking with the tech i went with what they recommend which is msd coils and msd wires with the acdelco plugs!!!! runs great with the bbk throttle body and headers ...but im going to see what happens when i disable the torque management with the diablo sport!!!!...OEM PLUGS ALL THE WAY... our trucks are picky with plugs trust me im a service manager and tech and i have had to warranty customers plugs cuz something other than acdelco was in the truck and made them run weak..jus my 2cents

 

[puckhead]

NGK TR-55

NGK TR-6 for Nitrous

+100

and gaped at .04

 

[bravo2]

How many are using ac delco gapped at .04 and also using msd 8.5mm wires and msd coil? I am about to change my plugs and wires so like to know before i do them.

 

[t_ahan]

msd is bad

i have not had good luck with the msd coils and wires...oe coils and wires r best....i jus ordered 2006 vette z06 assembled heads and cam,lifters,push rods with comp rockers ....i hope it will work on my lq4

 

[bigg]

""""""""""" e 3 """""""""""""" plugs

 

[t_ahan]

e3 ..u think they will help msd problem

my msd coils keep going bad and start misfiring....i have tried numerious solutions....plugs wires new set of coils...bought everything msd tech after a 5 hr walk through on the phone thought could work and still happened...i feel the factory set up really lets my truck pull and runn hard all day every day...i drive it pretty hard and it is mos def reliable with the oem ignition with the mods i have!

 

[Slammedchevy01]

So the OEM ACDelco Iridium spark plugs are the OEM factory for my 03 tahoe 4.8? I got 80k and it has a little miss and the shop recommended changing the plugs. Sound about right for 80k?
Are these them? Anyone gap those to .04 yet???
http://cgi.ebay.com/ebaymotors/8-AC...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

 

[DenaliWhip]

This informative thread, has answered my question on spark plugs and I just wanted to say thanks to you guys. I just purchased 04 Denali, am stock w/ no mods and wanted to tune it up its at 109k.

Looks like im going with stock replacements Ac Delco.

 

[withac]

Im running NGK. 55's I think. Several people on here have em. Works great and if you make the gap .04 even better!

I'm running NGK Power Plats, it's been a while since I installed them, are they the same as the TR55, that sounds real familiar. I changed them at around 90K and replaced the wires too, saw an immediate increase in mpg.

 

[TqMnster]

ACDelcos gapped to .04 and new wires got my truck running like a top again. Picked up all my missing gas mileage at 145k miles. The plugs the previous owner had it in were NGKs gapped to .065 and the .04 runs soooo much better!

 

[withac]

ACDelcos gapped to .04 and new wires got my truck running like a top again. Picked up all my missing gas mileage at 145k miles. The plugs the previous owner had it in were NGKs gapped to .065 and the .04 runs soooo much better!

The NGK's (the NGK site refereces a G-Power TR5GP but I'm sure it was a 55) I put in were pre gapped and in fact NGK said not to try and gap them as you could damage the very small center electrode. They came gapped at .04

 

[TqMnster]

I didnt look too hard for a number but I did check the gap and they were all .065 and werent in the best of shape. I've always had good luck with NGK plugs. Just went back with acdelcos (pregapped to .065) and gapped to the recommended .04 and it runs noticably smoother!

As far as gapping the ngks the electrode does come to point which I could see being pretty vulnerable. I would gap them down but do it very slowly to keep from going too far. I would not try to spread it any though...

Edit: Theres no telling how long those plugs have been in there so I'm sure NGK started pre gapping to spec for the specific application to avoid people breaking the electrode trying to do it their self. I'm sure these were older plugs, they sure looked to be...

 

[Zed 71]

Yep OEM or NGKs. Do not use Pulsars (or whatever they are called), E3s, or plugs with 4 tips (I think Bosh 4+s).