I have A 2004 F-150 4.6l V8, i've noticed a clicking/ticking noise when i drive slow maybe around 10 to 20mph, and when i come to a complete stop and my truck is still in drive, it clicks if like its a grinding noise. i do race it not alot but i have, could the racing have caused the problem?, i keep up with the maintenance, oil change etc... if you have an idea of what it might be please let me know, your help will be much appreciated. Thanks

 

Exhaust manifold bolts good between them and H pipe?