28mpg to 45mpg city/highway

[Red Horse]

I change my spark plugs and my mpg increase, I think the oem japan spark plug suck, cause since I got my car brand new im just getting 28 to 32 mpg and now I replace it with USA denso spark plug from toyota dealer, its a huge jump of mpg 45mpg is like a hybrid now.

[Kaotic Lazagna]

Nice, I didn't notice any mpg change after changing mine. In fact, mine dropped a little for a while, then became normal again.

[tanof]

What was the condition of the original spark plugs? How many miles did you have? I have 60k, should I change the plugs now?