Do you have an HR or a DE motor?

If you have the DE motor, then you had platinum plugs from the factory and most likely should have changed them well before 90K, and hence your notable change in performance.

The HR motors came with a higher quality iridium plug that is fully capable to extended service intervals. That's not to say you may not benefit from replacing a tad sooner than 105K (like maybe 90K), but the OP has 46K on his car; replacing his plugs at this point is just wasting money.

 

Aahh, I see. Mine is the DE. I assumed they were iridium on all of them. I just replaced them with iridium assuming that. I stand corrected. Party on, Wayne.

 

Thanks to all of you for advice! I think I'll stick with mine for now and just get the TBs cleaned.

 

I changed the plugs, cleaned the throttle bodies and it made no difference. My mileage still sucks, only 19.8 mpg with mostly highway driving and light throttle input.

 

What weight oil are you using? You have a clean air filter? What are your mods? I get 24mpg. Had it up to 26 but that was when I was hypermiling like a grandma.

 

I am right there with you on the mileage! synthetic oil, clean air filters and clean intake.

Are you using the on board computer for these numbers because that seems waaay too good? Calculating mileage on a full tank of gas, then refilling is the only way to check time and time again for accuracy.

 

No, those are tripdometer calculations. I'm telling you guys; hypermiling. Paying attention to the path of least resistance, knowing how much of an incline can keep you coasting in neutral, high treadwear tires pumped to 50psi. Never stop at lights if you can help it. Always keep enough space to not have to use your brakes, etc.

For instance a 4 lane freeway can have 4 different paths of resistance. Next time it rains, look at how it flows down a particular part of the street. That's the path of least resistance. Always try to keep going in the straightest line possible. I'll even continuously change lanes to keep from having to make too sharp of a turn. Haha

 

I just realized I thought this was a different thread. Haha I was talking about this in another thread. Kinda seems outta place here, but I was saying I used to own a first gen Honda insight that got 61mpg and I was really into hypermiling and it does help a lot.

 

Ha! that's funny! when you replied back, right away I thought you should be driving a Prius or something. No point having a G if you are going to baby it! The mileage sucks for a purpose.

back on topic - as for plugs, 46k should be fine still. will be changing mine at 85k even though I expect them to look decent. Just got the iridium's, just need a little time to get them in

 

Well, my opinion is that if your car is running tip top you should be getting somewhere around the EPA estimates. I still **** on bimmers and WRXs all the time and I cruise at 70-80. I by no means misuse this car as a hybrid wanna-be. I just do what I can when I can. My car is efficient as possible tho. K&N, z-tube, magnaflow, no resonator and I keep a well eye on my plugs and use 5-30 semi in 80 degree weather, so it all helps.

The insight was fun, just in a different way. It was like hot rodding for mpg.

 

For the people that changed their plugs, where did you get them from and which ones? My G feels sluggish and my MPG sucks, I think i need new plugs.

 

Buy the OEM plugs from Advance Auto. I paid $50 for all 6 of them including tax but that including a 35% coupon I found online earlier. You can probably find more coupon codes for advance auto online.

The part is Denso FXE22HR11 which is the exact OEM part in our cars and the same when I took my OEM old ones out.

 

AutoZone has the Bosch iridiums for our car and it cost me about $50 for all 6. Been runnin great for 30k miles.

 

You can get OEMs or the NGK Iridium plugs. NgKs are maybe 5$ more and are the better option. Up to you.

 

Would not get the Bosch especially if the OEM is the same price from Advance Auto. Top brands would be NGK or Denso. Bosch is considered worse than these two brands when it comes to spark plugs.

Looks like even now you can get it for $50.36 + tax with 30% off coupon TRT30.

FXE22HR11 is even listed in our owner's manual under specs for spark plugs, so you can be sure these are the right ones.