2003 Ford Mustang Mach 1 - Noise when above 2.8k RPM's


I have a 2003 Mach 1 Mustang, ( 4.6 DOHC 32 Valve)

When i start my car in the morning. Idling the car sounds normal and perfect with my SLP exhaust =) . But when I start to go on my merry way, when I’m in 1st and 2gear and I accelerate past about 2.8K rpm’s. I hear a really quite noticeable pingy/tingy sounds from my engine (Yes sounding like that annoying AMMCO commercial with people making noises). This will continue for a little while when i get into my normal running temperature, the sound isn’t as “Loud” so to say but still present.

I can comfortably say that there is nothing loose within the engine compartment. My spark plugs are tightened to the proper amount. I experience no performance lost as well.

This has just been a nuisance since I have purchased the car, it currently has almost 60k mileage and has followed the proper maintenance.

Anyone have any past experiences or recommendations?

Thank you,
-Mike D

You know, I used to have a 1997 GMC pickup with a similar problem. At highway speeds (and therefore consistent RPMs), there was a terrible metallic rattling noise from underneth the truck. Finally I figured out it was something loose in the muffler. I got a new muffler, and the problem was solved.

I wonder if there might be something similar going on here with some component of your exhaust system. Good luck.

It’s likely a piece in the exhaust system, probably a heat shield rattling. Have someone put it on a lift and tack anything that’s loose in place

Last i knew my exhaust is secured very well, im pretty confident it is comming from engine.

These SLP “Loudmouth” (the manufacturer’s term, not mine) exhaust systems have a valve that opens to allow freer flow of exhaust gasses. Open pipes don’t sound smooth, much to the dismay of some who try them, and your exhaust system is opening up more than the engine was designed for. Lower backpressure significantly and you’ll get that “racy” sound. Apparently it isn’t to your liking.

Even a small change, such as a ram air system, will alter the sound of your engine. That’s the price you pay.

Did u buy this car new?

No, i bought it used with 14k Miles

Wife’s friend has bullitt mustang. Think it’s same vintage. Do not know if it has stock exhaust or aftermarket.

An SLP exhaust is an aftermarket product.

The pinging from your engine is called piston slap, caused by you using the wrong grade of fuel. Wait until your fuel tank is near empty, then fill it with premium fuel that does not contain ethanol. Your engine requires 92 Octane or higher rated fuel.