What do you gap your plugs at? I changed my oil, plugs and air filter and lost mpg

[judogti]

Hey -

I bought my 09 limited with 58,000 miles so at 60k I put in new NGK Iridums (dont remember the model, I got it off this site though) that came pre-gapped to .41-.42

My last 3 tanks on the new plugs my MPG has gone down 60 miles per tank....

Im thinking it has to be the gap. What do you gap at?

 

[BlackWorksInc]

First off is it a V6 or V8? I also believe that information can be found in the Owner's Manual if I remember correctly.

I can't remember what the gap is for both engines off the top of my head though.

 

[riceandpho]

most are pre gapped at .44, make sure to check each plug, i gap my denso at .39

 

[chmura]

According to the Toyota manual you do not adjust the gap. They are already pregapped so just install them.

 

[4RunnerFan]

At that mileage, maybe try cleaning the MAF (Mass Air Flow) sensor.

 

[Greydog]

I've bought toyota plugs online and at dealer, some were definitely not gapped correctly, others were spot-on.

I've used the gaps spec in the manual, seems to be fine, no change to MPG.

 

[kris022]

I've bought toyota plugs online and at dealer, some were definitely not gapped correctly, others were spot-on.

I've used the gaps spec in the manual, seems to be fine, no change to MPG.

Yup!! There will be a few that are not gapped correctly so you need to make sure they are. I just changed mine last month and all are gapped @.41 and I used all Denso from the dealer. No effect in gas mileage.

 

[MikeInNH]

According to the Toyota manual you do not adjust the gap. They are already pregapped so just install them.

That would be the first manual I've ever seen that said NOT to check the gap of plugs before you install them.

Plugs are regapped at the factory...but things happen during shipping. My last tuneup I did...2 of the 6 plugs were off a little.

 

[ridefast]

My mileage didn't change after i installed new plugs @ 60k miles. I bought plugs from the dealer and checked gap, they were fine out of the box. My gas light comes on at 370 miles.

 

[judogti]

First off is it a V6 or V8? I also believe that information can be found in the Owner's Manual if I remember correctly.

I can't remember what the gap is for both engines off the top of my head though.

It's a V6 but I dont have a manual.

 

[luvmyt4r]

Yup!! There will be a few that are not gapped correctly so you need to make sure they are. I just changed mine last month and all are gapped @.39 and I used all Denso from the dealer. No effect in gas mileage.

Why do you gap smaller than what is spec? Just curious.

 

[judogti]

Why do you gap smaller than what is spec? Just curious.

This is what they came gapped at, I didnt change them. I had read a few threads on here that they came pre-gapped and that .41 was about right. I checked them and they were all right around .41-.43 so I popped them in.

The older ones were gapped a little wider, I just didnt think it would effect MPG that much. Im getting ~340-350 per tank now.

Think I should pull them out and regap them to .44?

 

[kris022]

Why do you gap smaller than what is spec? Just curious.

Fixed. I was reading the post above me and for some reason I put the wrong gap. Good catch and sorry bout that.

My taco had the same engine and it was indeed .41.

 

[BlackWorksInc]

That would be the first manual I've ever seen that said NOT to check the gap of plugs before you install them.

Plugs are regapped at the factory...but things happen during shipping. My last tuneup I did...2 of the 6 plugs were off a little.

This is absolutely true, always double check the gap on plugs because they can get dropped, dinged, ect and the gap changed. Sometimes they even get misadjusted from the factory.

 

[2big4arunner]

I always suggest checking the gap as well. I have seen some really really bad units go into vehicles because someone down the road dropped it and it landed just right to change the gap. I see a lot of boxed plugs come with the cardboard unit on them but they might have been bumped between here and there

Looking around I see the gap for most plugs is preset at .044. I haven't been able to get a service manual without it being a zip file so when I get it unzipped I will find out if I am right or wrong lol

 

[riceandpho]

i think the manual i read was it 1.0 to 1.1 mm (0.039 to 0.043 in.)
out of the 2006 repair manual, service specifications , 1gr-fe ignition

i think the smaller the gap is better, when the plugs worn out, they do get bigger.

 

[riceandpho]

look for the 00301810.pdf in the 2006 service manual.

 

[Whitebeauty]

look for the 00301810.pdf in the 2006 service manual.

.035 try it you'll see why.

 

[luvmyt4r]

Fixed. I was reading the post above me and for some reason I put the wrong gap. Good catch and sorry bout that.

My taco had the same engine and it was indeed .41.

Haha. Oh. Ok. I was wondering why a person would gap smaller other than on a forced induction engine.

 

[wickeddreamzzz]

be careful

The plugs in my 4.7l are iridium plugs. They (denso & ngk ) take great care in pre gaping them for your specs because you'll mess them up trying to change the gap. Best advice is look at all 6 or 8 and if you have one or 2 wrong which really doesn't happen that often at all in my experience just return them for new. These (iridium) plugs will be damaged if you scratch the tips.