Over the past couple of months I've been experiencing a fairly loud tick noise coming from the exhaust/engine. Brought it in and got new cat converters (aftermarket, both sides), new plugs. The mechanic said I probably have an exhaust leak somewhere. Thoughts? It's annoying as all hell and pretty sure my fuel mileage is suffering from it. What am I looking at in terms of cost to get this repaired? What could it be? Anything common for this truck? The tick was there before I had the repairs done.

On a second note, I'm also having the brake light flash (brakes are fine, had them replaced last summer). Thinking that maybe it's due to a faulty light on the dash readings or a fuse for the light. It flashes randomly and sometimes if I hit the dash it goes out. Again, no issues mechanically withthe brake system that I can see.

Thanks in advance!

 

The 5.4 3V tends to tick for lots of reasons:

Loose spark plugs - check 'em
VCT Solenoids - unplug 'em and see if the noise goes away, or just replace them with ones from eBay or Amazon
Exhaust manifold leak - use sea foam and watch for leaking smoke, or feel around for air bursts
Cam Phasers - some people report running heavier oil like a 5w30 will quieten the noise, or replace 'em
Timing Chains/Guides/Tensioners - replace 'em

and maybe some more, plus the injectors make a lot of noise on their own.