Hi i recently traded in my xterra for an 04 Titan love the truck, but when i first start it up and start driving it there is a small ticking sound you can hear in the cab. You can only hear it when i accelerate and withing a couple of miles you cant hear it anymore or maybe i just cant has anybody experienced this problem before. The truck has 45000 miles. My first thought at first was it was an exhaust leak but since it seems to stop and a muffler shop said there are no leaks i don't know. My second question is when i took the truck to Firestone for them to check to make sure there was no major problems they said it would fail and emission test because of the exhaust. The muffler shop thou said Nissan intentionally placed a hole in the exhaust to let condensation drip out is this correct?