Changed plugs, gas milage took a dump

[americanuck]

Maybe I'm missing something obvious, need more coffee or something but that is an increase in mileage, not a dump.

In freedom units I was getting about 21.5. Now I’m getting between 18-19.5 MPG. I should have included that in the beginning.

In Canada, to show economy we count how many liters we used to go 100km. So bigger number = bad lol.

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[Davexxxx]

In freedom units I was getting about 21.5. Now I’m getting between 18-19.5 MPG. I should have included that in the beginning.

In Canada, to show economy we count how many liters we used to go 100km. So bigger number = bad lol.

Gotcha, I didn't read carefully enough.

Another cup of coffee it is

 

[wayne1948]

If you want to check fuel per gallon you need to fill the tank up full, drive until it is almost empty then fill up again. Divide the miles or km by number of liters. That is the most accurate way. ALWAYS CHECK GAPS. Always! Mistakes at factory’s happen. It’s not your air cleaner if it is new. White smoke is water. But living in Canada it could be condensation in the exhaust pipes. Does it smoke all the time even after a long drive? Indexing plug is always a good idea. If you have a slight rough idle it could be 1 bad plug even being new. I get 17-18 miles per gallon with K02 all terrain tires which are heavy,
On my 2021 power boost. But I drive fast.

 

[Gooddog1949]

Hey all,

So im halfway decent around tools and maintenance. Normally basic maintenance on all my cars I’m happy to do. I got a new to me 21 with 160k km (100k miles). Got it for practically nothing, and it ran great.

I was getting about 11/100km on each fill up using premium.

Since it was due for service, I got out the tools and changed the plugs and engine air filter. And wow… now I’m getting 12-13/100km. I used motorcraft plugs and I do know that 21 had two types of plugs. Mine is job 1 and I verified as I pulled one out that it matched what I put back

I’m not getting any error codes and I took off the boots and checked everything. Just anecdotally it feels like there is less power.

I’m tempted to just get all new plugs, boots, coils, the whole thing. But money. Anybody smarter than me have any troubleshooting or thoughts?

If you was getting about 11/100km on each fill up befor changing plugs and now 12 to 13 per 100km would that be more km per 100?

 

[Les_Garten]

Did you disconnect the battery for any of this?

Does it produce smoke after it's warmed up?

How long had you been measuring the average(when was it last reset before the plugs)

I always check and gap plugs, plenty of youtube vidz I'm sure. Iridium plugs can be tricky...

Is it white smoke or light blue?

Do you have the old plugs? If so, take into natural light and take pictures and post them.

 

[DT444T]

If you was getting about 11/100km on each fill up befor changing plugs and now 12 to 13 per 100km would that be more km per 100?

"more km per 100" would be "more km per 100km" if all the units were there. That would be like saying you are getting 21 miles per mile. OP is leaving out the unit of "liters" in their "11-13 liters per 100km."

In freedom units I was getting about 21.5. Now I’m getting between 18-19.5 MPG. I should have included that in the beginning.

In Canada, to show economy we count how many liters we used to go 100km. So bigger number = bad lol.

 

[ANZAC]

With that much mileage on the truck, I'd reset the ECU (disconnect battery for whatever people say in the forums here). It may have over-corrected for the old plugs - with what they call "long term fuel trims" that are learned.

Also I assume you gapped the plugs before install?

 

[cujet]

Winter blend fuel is one possibility. Did you save the old plugs?

 

[Jerome10]

Winter blend fuel is one possibility. Did you save the old plugs?

This was my thought as well. I don't know when this change normally occurs, seems a little early in September but maybe not, especially in Canada.

I've never once noticed anything different in a car after changing plugs. And my last Corolla I let them get so low the tips were nearly gone (I don't think I got the right type of plug and drove too many miles). Still didn't notice anything different.

 

[DT444T]

This was my thought as well. I don't know when this change normally occurs, seems a little early in September but maybe not, especially in Canada.

I've never once noticed anything different in a car after changing plugs. And my last Corolla I let them get so low the tips were nearly gone (I don't think I got the right type of plug and drove too many miles). Still didn't notice anything different.

Summer blend is done for the year in the US. IDK if that means we're on a winter blend but we're not on summer, anymore.

 

[americanuck]

Hey guys. Apologies for the delay, I’m just getting over pneumonia that took me out for a while.

I haven’t had a chance to pull the new ones out and double check the gap, but I do have pictures of the old plugs.

I’ll do a battery pull whenever I get a few minutes under the hood at the same time I double check the gap.

It’s a thin white smoke after it’s been running a while. I was on a 500km road trip. I stopped and had to run in the store after about 200km. Left the truck running, and when I came out is when I noticed the thin white smoke

I’ve put about 3500 km on the truck since changing them, and I do the math based on fill up, not just by the screen.

I don’t think they’ve switched to winter blend yet, I think that normally happens late October.

Again, I appreciate all the comments. Just help my brain think of things. I’m handy with tools, but I’m not a mechanic. I’ve never experienced this, so it’s strange to me. Which is why I defer to people who likely have better ideas than me.

 

[XLT22]

Lower RVP fuel blend has already occurred down here so I assume the same for up there.

 

[Aonarch]

I didn’t check the gap. Mainly because everything I read screamed at me not to touch the gap. But they didn’t seem drastically out of whack. But easy enough to pull out and check.

Didn’t really smell any different. I lingered near the exhaust for a minute to try to smell anything, but didn’t get anything. Just normal exhaust smells.

For the position of the gap, pardon my ignorance, but how would one check for that?

You always should check the gap. Feeler gauges are best. The cheap circle tool can damage the electrode.

 

[travisN000]

I had issues with rough idle after replacing one of mine. I suspected my torque wrench was not working properly and was able to confirm, but had to drive the truck to the store to get a new torque wrench. replacing the torque wrench and fixing the torque / indexing solved my issues.

 

[travisN000]

I realize this is an old thread, but I just figured out that if you put your VIN into parts.ford.com, and search/select a part (for example spark plugs), at the top of a part listing, or left panel of a parts search it will tell you your build date (red square below, verified to my door sticker):

..having said that, if you are looking for spark plugs, make sure you read the fine print on the 2021 model year, as it appears the plugs changed in July:

If my reading is correct the torque spec is also different with the newer non-tapered gasketed plug requiring 18 ft-lb / 216 in-lb / 25 Nm, and the older tapered 11 ft-lb / 133 in-lb / 15 Nm
(please correct me if I am wrong!)

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