Checking engine performance after spark plug change

[phantomlord]

Hello,
A couple of weeks ago I changed filters, spark plugs and oil to my 2006 Yaris sedan.
The car accelerates just fine, no weird vibrations or missed firing as far as I can tell.
That said, the engine noise while doing it may be a bit off... I also unsure about the fuel economy. Since both may just be my imagination, what is the quickest way of checking if all the cylinders are firing properly without taking apart the whole thing?
Thanks!

[RedRide]

If there are no vibrations at all RPMs and it is running just fine you do not have an ongoing misfire problem.

Why do you suspect a misfire?

[ilikerice]

curious.. what type of filters did you get and which spark plugs did you go with? How many miles are on your car?

The ecu will pick up any misfire that happens at least 2 times with in a certain amount of time. you will get the "check engine" light if you have a misfire on any cylinder. either a particular one (Cyl #3 misfire) or a (Random misfire) codes, sometimes both

[phantomlord]

Well, as I mentioned it could very well be my imagination... I suspected misfire just because I think the engine is making a lower pitch noise than I was used to, because the spark plugs had just been replaced. BTW, they are NGK plugs and I am under the impression that the car may not be making optimum km/gallon (I rouhly estimated around 38km/g in mostly heavy city traffic, but I really do not have a personal number to compare to).
If you say misfires would trigger the check engine light, then I guess it is not the case and I should get psychiatric help.
Thanks!

[Focus_Sh1ft]

What gap are the plugs you used?

[RedRide]

Comparable NGK and Denso plugs are the same and there should be no difference.
I got a new Celica GT in '02. Some came stock with Denso plugs and some came with NGK.
Mine came with NGK.

BTW The Celica GT used the exact same plugs as the Yaris does.
In fact, I have a set that I never installed in the Celica (now sold) and they will eventually be going in my Yaris.

[Kaotic Lazagna]

I changed my spark plugs and noticed no difference in power (still early to tell mpg). My exhaust seems like it got a tad bit louder and has more of a gurgle sound when decelerating (which I like). Aside from that, no difference. lol.