I run Delco irridiums in all my GM vehicles. Excellent plug.imho

 

I replaced mine at the 100k mark with AC Delco OEM's. The originals still looked remarkably good though, I probably could have even just regapped them for another 100k of use!

 

How did u get the front plug out , with it being under the wiring harness. Was able to change the other ones with no problem.

 

LOOK CLOSE , you can move the harness,
i "wasted" mon ey and did mine at 60000, nervous about long thread plugs in aluminium because of previous old car galling and threading problems. i had no trouble with the h3 plugs, saved the old ones!! ill put them back when im older and grayer.
i added a tiny amount of anti seize on new ones

 

I have an 07 H3, does anyone know if I get a basic tune-up/change spark plugs if that will improve my fuel efficiency. Shop was talking about replacing a throttle body sensor that will run 900 dollars.

 

This thread is pretty old to tack on another question.

How many miles on your truck?

Get away from that shop quickly. The Throttle Body (TB) sensor is built into the TB, the sensor itself would not be changed, they would simply be replacing your TB. A brand new AC Delco TB is $230 or less, 4 bolts hold it in place, all that has to be done to replace it is to remove the intake, unplug the electrical harness, unplug the EVAP hose, remove 4 bolts, and swap it in. While the intake is off, all 5 spark plugs are directly on top of the engine with nothing in the way, one bolt hold the coil on each plug. The AC Delco plugs are like $3/ea. Book time to do both is less that 1 hour, but let's just say 1 full hour, even 2. Is their hourly rate $655 (Parts $245 - $900 quote = $655), or $327.50 if it takes them 2?

TB with couple coil packs below covering the spark plugs.


There is no "tune up" per se for an H3, they use a distributorless ignition with coil on plug packs. Spark plugs will easily go 100K miles before needing replacement. So unless your truck is running like crap from spark plugs that have gone past their life cycle (over 100K), changing plugs won't do much of anything for fuel economy.

If you have never cleaned your TB and MAF sensor, that is your "tune up". There are threads here on how to do it, forget that shop, do it yourself, including spark plugs if you want.

 

I am having a problem with the RPM dropping at stops. did you ever figure it out

 

Figure what out?

Search "false stall" here at HF. Read away, but the short list is in the FAQ section here. Acts like it wants to stall/rough idle -No CEL -What To Do: