I changed my spark plugs about a week ago and I am getting terrible gas mileage and maybe it's just in my head, but it seems as if it may be running a little rougher too. I had the NGK platinums in but switched to the coppers.
Now,I have read that people change from platinums to copper with no problem.

When gapping the plugs I used the wire kind. I adjusted the tip(.044) until there was just a little resistance when pulling the spark plug gauge out. Is that how it's supposed to be done? Do the platinums have to be gapped? I tested the gap in my old plugs(plat), and the gap is smaller than .044. I just would hate to have to spring $60 for the plats to get my normal MPG back. Did I do something wrong here?

 

Shouldn't be running rougher than before even if you used coppers. Put the old plugs back in and see if it runs smooth again

Have you changed out any other tuneup related parts?

 

what do u mean u gapped it with the wire kind? wthat?

 

here: http://www.gokartsupply.com/img/32-1707.jpg

or here: http://www.cars.com/advice/caradvise...ugs_image2.jpg

etc.

 

OoOoO thats interesting, never seen that before.. lol

 

Live and learn... or maybe in todays age, "Browse and learn"

 

arent the NGK ones already pre-gapped ?

 

The platinums are, but the coppers aren't.

 

check your codes?

it's possible something isn't seated properly.

 

Coppers come pre-gapped if the part number was BKR5E-11. If they didn't have the -11 on them they weren't pre-gapped, but I've never seen a set that WASN'T pre-gapped.

Anyways I personally thing this is in your head.

 

Maybe the running rougher part is in my head but the 320 miles instead of 410 miles to the tank sure isn't.

The reason I gapped the coppers was because I have read on here that they weren't pre-gapped and the platinums were. But even if they were pre-gapped isn't the gap still supposed to be .044?

I just need to know if I need to do some more gapping. If all else fails I will buy more copper plugs and leave them as they are if they are indeed pre-gapped.

Thanks for the responces.