Engine issue?

[ac2awest]

Hello, I have a 04 Mach with 60k. I have noticed lately that when I am driving at highway speeds the car will suddenly make a loud sound and the car will shudder for a quick second and then return to normal. it kinda feels like hitting a huge patch of water and the car slowing down suddenly but it only last for a split second. I have not been able to notice any drops in rpm or speed because it happens so quick. everything is stock on the car. Any ideas? Thanks for your help!

[birdman941]

Fist if you have not replaced the plugs and fuel filter yet,
I would do those first.
Most cost effective way to rule them out or fix it.
After that, coils, fuel pump, grounds, etc.

[ac2awest]

Thanks for the reply. I just did the fuel filter so I will try the plugs. Thanks!

[03mach1]

Do you have the A/C or Defrost ON? IT will kick the compressor on / off and feel like you loose power.

[ac2awest]

I have had the ac on and off when it happens. The jolt it gives is 10 times stronger than the ac being turned on.

[XSELLR8]

I vote the ignition coil on plugs (the part that attaches to the spark plug). Same issue on my 01 GT and my brother's Mach 1. Get OEM replacement Coil on plugs set. :3amin: Get all 8.

[ac2awest]

Thanks for all the replys. This at least gives me a place to start.