Possibly an exhaust leak?

[98EXPY 5-0]

I just picked up a 98 Expedition XLT Special Service Package (Police vehicle), 5.4L.

264K on the truck, 97K on the motor and trans.

It has a ticking coming from the driver's side. It responds to RPMs, meaning it is quiet when I am coasting, but sounds like a machinegun when I step on the gas. I am fairly sure it's an exhaust leak. Not sure if it's the manifold or the donut. Not really sure how to check except to put my fingers in and see if I can feel air. Is there a better way? I figure if I pull the wheel well liner out, I should be able to get at most of it. Is either the donut or the manifold gasket hard to do in the driveway? I have fixed lots of things on several vehicles, but I don't have access to a lift or the ability to remove the motor. I just use ramps and jackstands in the driveway.

 

[Catatonic]

Good chance its a broken manifold stud......not uncommon.
Look under the fenderwell with a flashlight and see.

 

[ELVATO]

Spray soapy water all over the place and look for bubbles? Would probably have to do it with a cold engine so the water doesn't evaporate.

 

[lakmflx]

This may seem like a farfetched thing to check but is happend on my friends Expy. Check the oil level for the motor.. In my friends case the motor had oil in it but it was soooo low it wasnt reading on the dipstick and was causing the same sound you describe.