Hey guys i have 70k on my G6 and have noticed my gas mileage isnt very good. I have a clean air filter, good tires and pressure so im hoping changing the plugs will help. I got the factory AC Delco plugs. I have a 2.4,is there anything i should know before changing the plugs? Will changing them help my mileage or what else could i be missing? I thought maybe an o2 sensor but no check engine light is on. Thanks in advance.

Thow a bottle of Techron in your tank!
http://shop.advanceautoparts.com/wcsstore/CVWEB/staticproductimage//N3232/large/7080568_chv_65740_pri_larg.jpg

Try Seafoam! It does wonders, but yes change the plugs that should help, I just bought AC Delco Iridium plugs for my GT, have yet to change them because the rear plugs are going to be a b!#ch to do, but on a 2.4l it shouldn't be hard.

ok thanks for the advice. now this seafoam and the techron, is this something that i have to keep buying over and over? im under the impression that if a car is properly maintained then the gas mileage shouldnt ever decrease.

Seafoam is a good product. You really don't need fuel additives, as for what they'll do won't negate the cost of the product.

Seafoam is best used by removing the brake booster vac line, and suck in about 1/3 of a can of seafoam. The engine will naturally start to sputter and smoke out the exhaust but don't worry. Seafoam is one of the better products out there to remove carbon deposits where it matters most - in the head around the valves.

Replacing the plugs should have been done at 60K, which is probably why your mileage has suffered. Also, be sure to check tire pressure, the underbody of the vehicle for broken pieces, air dam, etc that can cause excessive drag, and if you want to aim for a bit more mileage use synthetic engine oil after you seafoam the engine.

The remaining seafoam can be stored for another use or you can add part of what's left into the fuel tank. Seafoam suggests adding 1/3 can to the crankcase. I did once, but don't recommend it as you have to be careful not to put the engine under load (idle only) as the seafoam doesn't have the best lube properties under high pressure to act as engine oil and can cause damage if you touch the gas pedal. I've used it on several vehicles and have recently used Amsoil Power Foam, however the Amsoil product is easier to use, spray it into the throttle body (remove air hat of course). The only downside is that the G6 has a MAF sensor that you have to remove as well as the power foam isn't compliant for MAF vehicles only as it can trigger an engine light if you spray the power foam through the sensor.

oh no....Im at 117k with stock plugs....still motoring right along!

It is on the TO DO list though....

Im not a foam guy.....the techron cleans well enough for me. products that spew black smoke from my car make me antsy.... lol

oh no....Im at 117k with stock plugs....still motoring right along!

It is on the TO DO list though....

Im not a foam guy.....the techron cleans well enough for me. products that spew black smoke from my car make me antsy.... lol

Not to be racist here but there is no black smoke, only white. It doesn't smell the best, but it works. I had the heads off of my Durango (one oil change a year using Amsoil 5W30 synthetic) with heavy towing/hauling and they look like new.

117K on stock plugs is neglect!!

Plugs are good for 100k.....I wouldnt call it neglect.

Delco plugs are usually good for 100k miles. If after 5 years I don't have 100k, i change em anyway.

My Xterra had 30k on it when i bought it in 09, it was an 04. Plugs were shot :|

You may want to call me negligent but I have 171,000 MILES on my original set of plugs and the car still runs fine. I will be changing them today just to see what the difference would be. Also using the Iridium plugs. This is a 2007 G6 GT with 3.5L engine. Thanks for the warning on the rear plugs. Happy Thanksgiving.

whats the part number of the Plugs that you got??

Spark Plugs don't last forever. I'm sure that they would last longer if they are the higher grade and the Fuel System is in good condition. These cleaners that are being suggested will only clean the plugs and cannot correct for wear. Check the condition of the plug to identify a problem. Reading the Plug can help tell you how the Engine is doing.
Take a look at these;
http://www.oreillyauto.com/site/c/detail/ATL2/APP606.oap?year=2006&make=Pontiac&model=G6&vi=1432754&forcedVehicle=true&pt=03435&ppt=C0334

5 year warranty with unlimited mileage! I know what I will be putting in my G6. I average around 30,000 miles a year so...100,000 + miles makes these a great buy. I don't know what time has to do with a Spark Plug.

What are you gapping them to?

I am using Autolite XP606 about $7.00 each. I am gapping them to 0.040 per the 3.5L 2007 G6 owner's manual. I've taken the front three plugs out. After 171,000 miles the three had a gap of 0.054. I'm looking for hints before attacking the rear three plugs.

i did mine a few weeks ago...my hardest part was getting the boots off, after that they came out easy, to put them back in I put the plug in a 6" piece of hose and they screwed right in.

I used seafoam in my wife's 99 Ford Taurus and it is amazing! I always hated driving that car and I felt bad for making my wife drive it while I drive the G6, but I don't feel bad anymore. The car would hesitate a lot and was slow on the throttle. It felt like it was always a struggle just for the car to run. It also had a check engine code that said it was running too lean. I went to go use the seafoam and one of the spark plugs was so loose that you could hear it rattling. I tightened that plug back down then used the sea foam through the vacuum hose into the engine, some in the crankcase (not while it was running though) and the last third into the fuel. Of course, a ton of white smoke came from the exhaust as the sea foam and engine deposits burned off. Now, I cleared the check engine code and it hasn't come back on and the car runs a whole lot better. It turned out there was also a code for a misfire in one of the cylinders (it must have appeared after I checked it the first time and got the lean code) and I guess it was from that spark plug coming loose. None of the codes have come back yet and now I don't mind driving the car or letting my wife drive it. That stuff does wonders though and it was way overdue! Now all I need to do is get the tires balanced, aligned, and rotated so it doesn't vibrate like crazy on the highway lol. That's an expense I'm willing to put off a little though since we don't drive that car a whole lot anymore. The car has held up pretty good considering all that its been through: a few wrecks and a college girl who knows nothing about car maintenance. Her dad has always been the maintainer of the car and used to be a Ford mechanic but while she's been at college it hasn't had a chance for her dad to work on it as much as it needs. It's a reliable car though considering.

I used seafoam in my wife's 99 Ford Taurus and it is amazing! I always hated driving that car and I felt bad for making my wife drive it while I drive the G6, but I don't feel bad anymore. The car would hesitate a lot and was slow on the throttle. It felt like it was always a struggle just for the car to run. It also had a check engine code that said it was running too lean. I went to go use the seafoam and one of the spark plugs was so loose that you could hear it rattling. I tightened that plug back down then used the sea foam through the vacuum hose into the engine, some in the crankcase (not while it was running though) and the last third into the fuel. Of course, a ton of white smoke came from the exhaust as the sea foam and engine deposits burned off. Now, I cleared the check engine code and it hasn't come back on and the car runs a whole lot better. It turned out there was also a code for a misfire in one of the cylinders (it must have appeared after I checked it the first time and got the lean code) and I guess it was from that spark plug coming loose. None of the codes have come back yet and now I don't mind driving the car or letting my wife drive it. That stuff does wonders though and it was way overdue! Now all I need to do is get the tires balanced, aligned, and rotated so it doesn't vibrate like crazy on the highway lol. That's an expense I'm willing to put off a little though since we don't drive that car a whole lot anymore. The car has held up pretty good considering all that its been through: a few wrecks and a college girl who knows nothing about car maintenance. Her dad has always been the maintainer of the car and used to be a Ford mechanic but while she's been at college it hasn't had a chance for her dad to work on it as much as it needs. It's a reliable car though considering.

Not to go off topic, but I totally concur!

I bought my '99 Taurus new (dealer demo for under $19K Canadian) with the 6 disc CD changer and the whole vehicle still runs like a top. Passed 220,000kms on a trip to see the Steelers a couple weeks ago. One problem was with a bad seatbelt retract spring that was replaced under warranty, and the latest was a loose wire going to the fuse box where the headlights would cut on/off at repeated intervals. An hour at the dealer and it's back to running great.

I've been running Amsoil in it for the last half a decade (one oil change a year) and have thrown an Amsoil EA air filter.

I threw an Amsoil air filter into the G6 GT as well. However, I must admit that the 7 year newer G6 has had 4 warranty related problems and another two that weren't covered and I just passed 50,000kms! Downright terrible. Total time lost to these problems were 8 business days and one full weekend. Total time lost to my '99 Taurus with over four times the use - half a day.

Every time I wash/wax the Taurus I have to applaud the guys at the Ford Chicago plant as I read the sticker in the far back corner window "Proudly Built in Chicago"; Job well done.

If I need the space or plan to utilize it as an RV/tent, I drive my Durango R/T on road trips. Otherwise, if hotels are on the menu I won't think twice about hopping into the Taurus. The G6 is more my putter around town car, and to be frank, if the resale was better I'd seriously think about putting it up for sale.

Taurus Pro's over the G6:
- roomy
- well geared for modest 145hp
- large trunk
- trunk pops fully open when activated remotely
- better winter driver (using winter or all season tires!)
- OEM speakers are still flawless

Taurus Con's
- heavy for size (over two tons)
- minimal aftermarket radio selection
- no engine oomph over 4000rpm
- 6'2" rear passengers rub headliner in back seat (my smaller Dodge Spirit had more head room!)

G6 Pro's over my Taurus:
- electronic speedo (km/h to mph is easily done)
- quick around town
- best car I've owned to have to do an oil change on
- auto stick gear selection
- has engine life over 4000rpm
- better handling car in almost every respect
- light on its feet around town, even with a few passengers

G6 Con's (as family sedan's go):
- trunk doesn't fully open, you have to get the fingers dirty every time
- tight seating, side bolsters not for everyone
- both front OEM speakers didn't even last 24,000kms
- low profile tires allow for minimal tread life

I drive the G6 harder as was it's nature, unlike my Taurus so both cars return similar mileage numbers. Now, I've been using copper core spark plugs on my Taurus for the last 130,000kms, which I replace every 40K kms for best reliability.

I won't leave the G6 OEM plugs in there until 160,000kms (100K miles) as I drive it hard. I know full well what it's like going too long on a spark plug - drilling heads isn't fun, so I'll replace them at 90,000kms to be safe, 40% earlier but for $4 a plug, it's a sound investment. Providing of course the car still operates well at that time!

The part that you mentioned about the trunk popping open fully on the Taurus is nice and annoying that the G6 doesn't do that. I wish there was some way to make it possible though, maybe a mod for the trunk arms or something.

Its great that you guys are getting a lot of life out of your plugs but like mentioned I would hate to have one sieze in my head or get worn and not drive the best. Its like oil changes too. The new oil can last 5000+ miles but for a small price why not change it at 3k just for peace of mind. Its a small cost to pay to keep your car happy. I'm not sure when I am going to replace mine but I will probably keep an eye on them and do them soon. The car has 33k and I just bought it so I have no idea the history of the plug. Also, original equipment is iridium so you guys should stick to that if you want top overall performance from your car. (ew, my work is rubbing off into my daily life as well, haha)

Changing plugs on 2007 G6, 3.5L Engine:
Hardest part is getting boots off of plugs without breaking wires. Even with a tool, I could only replace 5 of 6 plugs. Feared breaking the wire.
You can change the rear without taking out the alternator. Just label and disconnect the opposite end of the plug wires from the black panel near the rear of the engine. There are numbers on the black piece. Verify/LAbel the wires accordingly before removing them
Using IRIDIUM plugs gapped to 0.40 per the owner's manuel results in more responsiveness/power. MPG seems about the same. Key take away is that you don't have to take the alternator out to change them. It might make the plugs easier to access but for folks like me who are only marginally comfortable with maintenance on cars, removing the alternator could open a can of worms I couldn't deal with. Hope this helps.