"sputter sound"

Recently, I have noticed a sputter sound coming from my 99 tahoe. It seems to have started slight, and now more aggressive. It will not do it in an idle rev, but only in gear. It has 160,000mi, and I tried replacing the plugs, wires rotor, cap, and air filter. No change so far. It sounds basically like an old truck now and I can't figure out what causes that, any suggestions???

Could it be a tiny exhaust leak up front somewhere?

Yea, sounds like an exhuast leak, probably from the ehaust manifold gasket. If it's small enough, you won't hear it in idle in park or nuetral until there is a slight load on the engine, such as idling with it in gear.

In replacing the "manifold gaskets", can you simply remove bolts/nuts, pull back exhaust, and scrape/replace gaskets and replace bolts/nuts or is it more complex replacing them??? Thank you, Dan.

loosen the bolts and pry it back slightly. u may need to notch the gasket holes. if the original gasket doesnt come completely off, then the manifolds need to come out, and surfaces need to be cleaned.