I have been reading the threads about the sparkplug gap in our xBs and people have been saying that they are incorrect from the factory so it got me thinking about mine so I went out to the garage to take a look. I found that all my gaps were the same
at about .25 I have read that they should be between .28 and .32 Well I gaped them at .35 and I will have to tell you I was skeptical that anything would change but it did. The car does idle smoother and it seems to have better throttle response at take off.

Now I have not had any problems with the car and it ran great before but now it runs just a little better.

 

IMO, there is probably a reason they are set at a certain gap. I would find it VERY hard to believe that any manufacturer would roll out every car with an incorrect spark plug and then not say or do anything about it...

 

cost they figure you'll come back to the dealership for your first tune-up anyway.

 

Mine came gapped around .038 to .042 and by closing them back to the .032 the manual calls for, I have averaged 2mpg more and am not getting as much black build up in my exhaust tip. Car also responds better when I play rough with it.

 

imma gonna check mine this weekend

for the just wondering factor...

 

mine checked out fine well the color did for 21Kmiles they were all gapped around .38
so i regapped it to .32

 

sounds about like mine were...you should notice a little boost in milage i think now

 

my mileage was fine before i checked out i was getting around 33mpg in city driving

 

mine was fine before i corrected my plug gap too, however my exhaust tip was really black inside after just a couple of months. My milage jumped about 2mpg after the change though.

 

so wut plug gap distance should i set to have the highest mpg? thanks

 

just set it around .031-.032 for stock plugs