dtompsett

So... just replaced the very worn out spark plugs in the car... so worn that the gap was more than the .040" test gauge I had.

OE spec says .028 to .035 for plugs. I gapped mine to ~.028... and ya, I took it for a spin, and it actually does feel like it's got more power than it did with the old plugs.

So the question is... what's the best gap in that given range? Is it performance vs. economy?

squidix9

However I do find that if I go much beyond (+) .035 I start to foul the plugs. They foul pretty easily already, especially cold.

I check them often and I use .035, I haven't rried anything less.

audifreakjim

But like Mark said, at some point they will start to miss or foul. On a non-turbo car you should be able to run .032-.035 with no problem. I have to run mine at .027 or the thing will not light at 33 psi.