No, not +2 heat range... The Bosch +2 is their gimic plug with 2 ground contacts. +4 has 4.

 

I used to use AC Delco plugs but i just did a tune up and used E3 plugs and deffinitally noticed a difference in power and a little bit better gas mileage but the power was more noticeable!

 

Just a hint, but you will always notice a difference between old, worn out, plugs and new plugs. I still stick to the motto that if those plugs actually did what they say that they do, they would already be in these vehicles and not have to have infomercials to promote them.

 

i would not run e3 is any type of vehicle. i put them in a lawnmower once on a bet and had to replace them at the end of the season. they were shot, couldn't even start but different plugs in and it fired up. if they cant stand up in a lawnmower how are they gonna stand up in a vehicle

 

i recommend putting in what the factory emission sticker says it recomends. im only putting in Autolites now temeporarily until i fix my spider/intake and to take out the bosch plugs that are in it now. then after i will put the AC Delco's that i have for it. unless it runs fine with the Autolites afterward i may leave them in a little longer....

 

Wow, I put one in the my lawnmower and it was the best possibly that it ever ran after putting it in

 

this is such a debated topic.

i used to run the Champion Copper Truck plugs in my other "S" series trucks & gas powered 'Burb, and would put 50 to 60,000k on them with minor rounding of the electrode. never had any issues with them-ever.

but i've had waaaay too many people (on & off this forum) tell me these newer 4.3's run much better with the Delco's. this time around i went OE, since i got a complete tune up of AC stuff (originally bought @ the dealer) for $100 cash. can't beat that.

 

I installed Autolite double platinums for 4 months and they were bad. Bought AC Delco rapidfire's and it was like night and day...

Taught me a lesson....

 

I've always replaced them with what the book says. Be sure to gap them properly (the guy at the A/P store can tell you what is recommended and the gap). A little anti-seize on the threads isn't a bad idea either. It is a debatable topic like Oldskool says but I figure if GM installed them they must ne OK. I think mine are AC CTS 45, but check with the A/P guys. About the gap, they're almost never right straight out of the box. I've always had to open them up a little bit.

 

Sorry for bringing an old thread back to the top but I replaced the plugs with the standard factory Delcos and my 4.3 loves em. I noticed a decent difference, but that's probably because a couple of my old plugs had crud built up on them from age and possibly some light oil burning.