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Q: Could i have caused an engine modulation?

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I have a 2002 ford Taurus with the 3.0 L OHV. I recently replaced the ignition coil, spark plugs, and plug wires and the car runs great. However, i noticed that since i replaced those parts, i have a very heavy "modulation", or pulsing in my engine. I am very in tuned with my car and i notice the smallest changes. So this is making me nervous. Is this something i need to worry about? I fear i may have accidentally damaged my motor, since we managed to cross 2 spark plug wires and my motor was not firing in the correct order. (2 people trying to work on the motor at once and 3 wires ended up being pulled completely off at once) Would this cause damage that may explain the sudden pulsing tone? If it matters, we crossed cylinder 4 and 5, so as the firing order, it was causing my 6th cylinder to fire on 4, instead of 5, and my 4th cylinder was firing on 5 instead of 4.

My car has 201142 miles.
My car has an automatic transmission.

A: We have all at one time or another crossed ...

We have all at one time or another crossed spark plug wires. To date, it has not caused a problem other than the misfire from the crossed wires. So rest assured, it is highly unlikely that this caused any lasting problems.

As for the modulating, I can’t say I am sure what this is. My interpretation is you are feeling a new vibration or noise. Vibration are often accompanied by a noise. You also stated you are very in tune with your car. As a longtime technician, I can say I am as well. Establishing this, only the daily driver of a given car will be able to notice the smallest change in our vehicle. With this said, there is a very human phenomenon that we are all guilty of. Myself included.

If your still worried about what is going on with your car, you can have a technician check it out. Keep in mind, some sounds can be difficult for others to pick out of all the noises our cars make. So be prepared for an extensive test drive to help the technician hear your noise. I recommend the following inspection; Car is making a noise inspection which can be performed by a YourMechanic technician at your home or office.

Good luck!

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