View Full Version : Possible Spark Blowout On Old Ignition - Questions

10-14-2003, 11:10 AM
My car is a 1996 Mustang Cobra with the 4.6 32 valve V-8. Only engine modifications are off-road exhaust.

here's the dyno graph.

Notice the drop in power as well as random fluctuations past 5000 RPM. This is usually the area in which this motor shines the most, and the way power builds early in the graph, it looks as if it should peak around 280 RWHP, but instead, the power curve falls on its face.

I've inquired about this on many other boards, and there are quite a few people who have told me ignition may be my problem.

My car has 62,000 miles and has never had a plug-wire change. I changed the spark plugs (which were orginal) and the car seems to drive better now. My question is: Could the original Ford spark plug wires be worn to the point now that they aren't transferring spark correctly, thus causing the lapse in power at upper RPM's?

That's my question, I decided to post here because i assume ya'll are the ignition experts.


10-14-2003, 03:43 PM

It could be a problem. If the wire is breaking down it could be doing two things. It could be losing spark, secondly it could be noise. As a wire deteriorates noise(RFI) radiated out of the wire increases. This noise actually gets in the computer and can create major issues. It is something to consider, with the miles on the car it might not be a bad idea to change them.


MSD tech4