I've got this weird ticking noise which seems to be under the passenger-side floorboard. It's almost inaudible at idle but revving makes it more pronounced. It's not the vent/ac or radio or fuse/relay box inside the cab. I'm guessing an exhaust leak. The exhaust and o2 sensors are all under that section. A sound recording is attached. There's no check engine or any codes and all the live stats look fine and it drives fine. Recently changed plugs and wires but had no effect on this ticking sound. It's at 163K miles. Google suggests a bunch of possibilities in the engine but I really don't hear it with my head under the hood. Any suggestions on things to try are appreciated. Thanks, Clark

 

Have some put a GLOVED hand over the tail pipe with engine idling while you listen in the area you think the sound is coming from


Another test if its not exhaust sound
When engine is STONE COLD, i.e. sat overnight
Remove fan belt from crank pulley
Start engine, battery light will stay on
engine bay will be VERY VERY quiet without the fan
Listen, REV engine if needed
You can only run the engine without the water pump for 90seconds or so
Which is actually quite a long time when listening for a noise
After shut down put belt back on and start engine let it idle for 2 or 3 minutes and you are done

You can repeat this test as much as you want AFTER engine is stone cold again

And if there is no noise then noise was coming from a pulley on the fan belt, check each one
Except for the crank and power steering pulley each should spin with no noise

 

Thanks for the tips. I'm convinced now the exhaust coming out is strong enough and with some help, I believe the clicks come from the upper passenger side of the engine. Could still be a leak on the exhaust manifold I guess but since the engine is DOHC I'm thinking it's valvetrain related. Anyway, I've resolved to take the valve cover off on that side to investigate once I can afford the downtime. Will update this thread with what I find. Thanks