Looking to replace the spark plugs in my 2003 4.8L V8. Specs call for a .06 gap, but I've heard from a few people that using these better plugs (AC Delco) already pre-gapped to .04 would work fine. Should I stay with different/cheaper plugs and gap to .06 or use the more expensive .04 pre-gapped plugs?
Thanks.

 

considering that you may repalce the plugs in a vehicle 2 maybe 3 times in the life span of the vehicle I would go with...
1. The recommeded plug
2. OEM brand
3. if no.2 doesnt work go with no.1

Unless you have done some engine mods that require a different then recommended gapping, go with what has worked so far..

 

Also, NEVER trust that a plug is "pre-gapped"
Always gap the plug yourself. You don't know how many times the plug was dropped on its trip from the factory to your hands

 

Thanks guys. At the end of the day, i also sleep better knowing I haven't deviated from the specs.

 

Really?

Let me throw a curve ball at you. Called HALO plug. Do research on those before you buy something else. Gap? What gap? Better mpg? yes, indeed, - but who needs that, right?

just for starters:
http://www.lsgbrisk.com/products/trialresults.aspx

of course, he(Roger, I know him as I bought from him many times) sells those, thus GREAT results posted. But! I, personally, came across Ontario government research, when they tested their street cleaning trucks fleet, and had it proven in a year and off thousands of cars, that they DO improve mpg. Something like 1.4% I remember.

And just came across this one:
http://www.halo-sparkplugs.com/halohistory.htm

 

My father tested these in his park ave, as well as in his g\f's Accent. Both always recorded MPG before and after the plugs and both saw no improvement whatsoever.

 

Oh yeah. I remember hearing about those >.< . My buddy had some and never bought them again. Said they were a waste of money. He never saw a improvement in gas mileage. He drove his truck nicer than he did with his old plugs too. Said they were about as good as **** on a bull. Just what I've heard about them.

 

Well, here's something to chew on; after 57k, those "100K Iridium" plugs from the factory were almost ready to melt off the side of my truck. So it might be a mistake to trust ANY claim of extended life or durability unless you've tested it fully. And yes, I replaced them with stock AC/Delco Iridiums again, but I'm going to keep my change-out interval to 45-50K from now on. Pre-gapped. Ah, right,yeah. I've never gotten a set of "pre-gapped" plugs with any gap uniformity in 35 years.