Hello Im a Owner of a 4runner 4x4 My brother owns the 2006 3.5 H3 but i made this log in for him to use in the future. Today We Changed His Spark Plugs I went to the autozone I bought him the Spark Plugs and Sea Foam. Now We poured it in the crank case and in to the Gas tank. Then We Changed the Spark Plugs out I was Told the truck used Double Platnium. But as Requested from my older brother he told me to get the more expensive ones the Iradiums From AC Delco. When we Changed Them Out for those We Started the Truck and it just had a nasty Rough Idle and the CEL is on when it drives. My Question is Is it the Spark Plugs or is there somthing Wrong?

 

its the plugs. There are a few threads here about the same issue. You only wanna use factory oem plugs in these trucks or else they seem to go haywire. you should be ok once you switch them out again.

 

I had the same problem on my 06 H3. I just bought it a few months ago with 70000 miles on it. I didn't know if the previous owner took care of it, so i decided to sea foam it, clean the throttle body, change the fluids and put new spark plugs in. I went to the locale o reilys and picked up, what I was told to be oem ac delco Iradiums spark plugs. I put them in and cracked it up. It ran like SH@! and the check engine light was blinking. I took the wifes car (not a hummer went back to the store. The guy at the counter said Iradiums the only plugs it shows and an autolite platinum. So bought the autolites and when to the garage. on the way home I thought maybe the gap on the Iradiums plugs where off some how. Pulled the Iradiums checked the gap which where way off, gaped them the correct gap, put them back in. same problem. took the autolites out of the box, checked its gap. they where off too, not as bad as the Iradiums. put the autolites in. you guessed it, same problem. I said screw it and put the old ones in. H3 runs fine, no check engine light. I am just gonna leave the old ones in till 100000 mile. I wish i would have found this forum before I started tinkering with my H3. ONLY USE OEM PLUGS. It will save you a lot of time and sore knuckles.

 

The champion direct replacement plugs for the AC Delco 41--981 (2006 3.5L) 41-103 (2007+ 3.7L) 41-985 (2008+ Alphas) are also fine if you cannot get the OEMs easily.

Spark plugs are not sold "pre-gaped", they always have to be gap checked for the vehicle installed in.




On another vein.... Sea Foam is a waste of cabbage, loot, dough, cash, pics of dead presidents, moolah.

 

HaHA Doc,
Thanks for giving me another thing to add to the H3 - Waste of cabbage, loot, dough, cash, pics of dead presidents, moolah list.

#1 - Leveling kits / Reindexing keys
#2 - Throttle Body Spacers
#3 - Sea Foam

 

Years ago when I was a wee lad and worked at Autozone we we're instructed that any plug with a special tip, i.e. platinum, iridium, we're pre-gapped and if you did gap them you risked damaging the electrode.

I am not asserting either way is correct, I generally do check them because I don't trust the "pre-gap." I would like to hear a little more discussion on this...

 

I just pasted the 75,000 mark and feel that the engine isn't as smooth as it had been. With he AC Delco 41-981 shown to be replaced by the 41-103 and it seems this plug isn't working out too well, which non-AC Deloc plug is the best out that? I am looking at the Champion CHA 7981 or the Bosch BSH 4314 - any suggestions/recommendations?
Thanks

 

The Alphas take an Iridium? I searched the 41-985 and it shows as iridium.


Ok, as for Sea Foam i do use it on a rare occasion. I used it as a top end cleaner for my father's MB that had close to 200K on the clock. It was running like crap so I changes all filters and plugs. Better but still pretty rough. SF'd the sucker and it ran like silk... of course once it ran well and I put 10 hours under the hood my dad drove it around the block- came home said good job and promptly traded it in. LOL Now I am sure my dad had barely remembered to change the oil most of the time on the car so very little if any maintenance was done on the car. SF did make a difference in this instance. Just my $0.02

 

I'm experiencing the same problem. I replaced the sparks with ACDelco iridiums 41-103, they seemed to be pre gaped .041, I gaped them to .043, which I read. Is that the problem? Based on the other reply's it doesn't seem to be. Is the H3 that sensitive? I also need help to resolve this!

 

Go back and revisit what you did. If you do not have a coil packs on straight and snapped down in proper position before you tighten the retainer bolt, you will have issues.

Since you chose to post in an OLD thread instead of starting a new one with more of your specific information (like how many miles you have on it and exactly what your symptoms are) it makes it more difficult to help. The best plugs for the I5s are AC Delco OEMs.