Very slight hesitation

[xpeteyjtx]

Here is the story...
My car vibrates like many 5.0s that I have seen. Well one day I decide to change out the plugs to Autolite 25s. After that, it seemed to run better (not as much vibration). But now, after about 3 weeks, it seems to have that vibration again. It also hesitates a little bit when I tap the throttle after it is idling (this is most observed when it is slightly cold and in gear). It also seems like it may have lost a little bit of power (that just may be my imagination though). So I am looking for advice, I don't get any codes, could my plugs be fouled? How do I know whether they are fouled? (Is it when they are black?) Thanks for the help in advance.

I have Ford racing wires and a MSD coil.

I gapped the plugs to .054 and the car idles perfectly (no surges)

 

[LX302]

Did you clean the throttle body lately and or adjust your TPS? Have the air and fuel filter changed last?

 

[90mustangGT]

Did you clean the throttle body lately and or adjust your TPS? Have the air and fuel filter changed last?

Good point. Also, what about the cap an rotor? At work, a problem I have seen a lot of is clogged fuel injectors, there are services that clean them, directly through the injector. A symptom of these cars is rough idle and hesitation. Not saying that is what it is, but very well could be. Another place to look is the charging system. A failing diode in the alternator will make the sensors go nuts.

 

[xpeteyjtx]

Sweet, thanks a lot guys

 

[HISSIN50]

If it misses with a steady throttle (requiring no TPS signal return change per time) would begin by running a cylinder balance test. It's a quick and easy way to check that each cylinder is contributing equally. If it fails, retest (it will do it up to twice more) with different criteria to help determine how bad the issue is.

Good luck.