2002 Ford Mustang hesitates, pings, spudders

Hi da7373, Welcome to 2carpros and TY for the donation

P0305-Misfire at cylinder no.5-You should check the sparkplug, compression and injector for this cylinder-

Also try cleaning out the EGR valve and test throttle position sensor and knock sensor might not be retarding the timing when the engine starts detonating/pinging, also check the fuel pressure if its within specs-

Yes the car does have a knock sensor. Secondly the EGR valve can be removed and cleaned. As long with the ports on the manifold can be cleaned to make sure it is not sticking.

The vaccum will feel kind of like a pulsing and that is normal because the egr vaccum regulator controls vaccum to it to open it or close it when needed. If you want to see if the EGR is causing the issue put vaccum on it and pull it up. If it starts to hesitate egr is functioning properly, if no change when vaccum is applied then the egr is probably stuck open.

A injector would start to fail after it runs due to the coil heating up causing resistance to go up thus causing the injector to flow less and less. A good test to do is switch the COP and the injector with say cylinder number 7 and see if the problem follows that. If it does its one of those. If not I would be checking for compression and wiring. Let me know what you want to do

You need to find out why the piston is touching the plug end-you sure you have the correct type plug and heat range