Please Help Flashing Check Engine Light At Speeds Over 80mph.

[Nokiashorty]

Hello all

I'm having this issue with my 2007 V6 Mustang. As I'm driving on the highway when I drive over 80mphs my car begins to putter and my check engine light(yellow) begins to flash. When this happens I've been letting go off the gas for 15-20 secs or so and the light goes off and I have accelerating power again.

While this happens if I try accelerating the car just putters and it feels like it has no power.

Here's what I've done on it already:
-new coil pack
-new spark plugs
-new spark plugs wire
-new air filter
-fuel injection cleaning

Also a week before this started happening I had a new harmonic balancer installed.

The original problem for getting the new coil pack, spark plugs, and wires was that I had a check engine light go on but not flash. I was having a misfire on cylinder 3 and 4.

After getting that's fixed is when I started having this puttering and light flashing.

Any ideas??

Thank you!

 

[Mustang5L5]

When a check engine light flashes, it indicated a serious misfire issue. It's usually a sign to stop doing what you are doing or you could seriously damage the engine.

So main question is why are you misfiring badly?

I assume you have a previous code on cylinder 3 and 4 prompting you to address the ignition components there? If you run the codes now, do you see any pending codes for the same cylinder?