Can anybody help

I have a 2003 mustang gt. I started my car as usual and I turned on my a/c. I took off from my residential street and made a u turn at the first stop sign. After I made that U turn I went from first gear to second and lost all power in the enigine, it start making a clunking noise associated with difficulty in a stable idle. I had to play with the fuel in order for the car to stay on. The car did die and it was very difficult in starting back up. I managed to get it home where it was very difficult to start and has a very erratic idle with that clunking noise. Anyone have any suggestions on this problem.

The clunking is very hard to diagnose over the internet. It may be helpful if you can get a video of the clunking and post it online. Where does the clunking seem to come from? Front of the engine? Back? Passenger side/driver side? Transmission?

Since it happened when shifting gears, are there any unusual things going on with the clutch? It may be causing the clunking if there is a problem with it.

I do have a video of this and I will post it.

I have my brother in law that is mechanic. He said that the fuel pump may not be sending enough pressure to the injectors.

The video is not uploading.

Sounds like you have broke your car, from your description this could be just about anything. if it was an older car i would say it sounds like your timing has slipped. the clunking would then be the engine not knowing which way to spin and rattling the internals.

My brother in law checked the fuel pressure and the pump is not delivering sufficient fuel to the injectors and is making sound like it slipped timing. The rattling is a clutch plate that needs to bhe tightened as a result of the irratic engine.

Here is a video of my problem. I changed the cats to a bassani highflow catback mid pipe system, new fuel pump, fuel filter and it is still running with a severe lope and it boggs down on low rpms, it revs real good though. Just the low rpms it bogs down.

There's no video.

Sorry, I could not load the file. I can send it via email but not load to this site. Thus far I have changed the EGR valve, MAF, Cat system to a Bassani High flow. One of the cats was severely clogged and since then it has thrown everything out of whack. The enigine sounds okay but the idle is up and down until it eventually dies.