Recently bought an 01 Excursion ltd, v10, 2wd, 126K. Starts great, accelerates fine, no smoke, good oil pressure, clean oil, no hesitation, no warning lights, good fuel mileage. It sat for about a year with the previous owner.
But, it has an odd sound upon acceleration or creeping up a hill (waiting in line at school). It sounds like an intermittent misfire. It's sort of a popping sound. It will somewhat replicate the sound in neutral at around 2-2500rpm.
I replaced the plugs, they were ok, ready to be replaced, but not bad. No change. Still noisy.
Wife doesn't like the extra noise. She's used to here denali. I looked at the exhaust manifold gaskets, they look intact, to extra soot. The donuts, from what I could see look ok. I don't feel anything with the engine running coming from those joints.
Could it be a leak under pressure? I'm sort of at a loss. Any help would be great! Thanks!