I own a 1994 Nissan Pathfinder 2WD. It has been an excellent vehicle, but recently I have noticed a "puttering" sound in sync with acceleration at lower speeds that seems to be coming from the engine. I do not hear this sound when idling, braking or on the highway. It is not a random or rough idling sound, it is a very systematic sound tied to acceleration.

I've checked the oil and other fluid levels, they seem okay. I've added "engine system cleaner" to the gas, but it did not seem to make a difference.

I would appreciate any diagnostic advice out there.

Leaky manifold maybe???? Is it mostly when the vehicle's cold?

Denis

Likely the infamous snapping exhaust manifold snapping studs. A problem that plagues most pathfinders. The engineers at Nissan didn't properly account for a small detail called thermal expansion that causes dissimilar materials to expand and contract at different rates. Although nissan does have a service bulletin concerning this, they will not recognize it as an engeneering problem. (Probably because it would bankrupt them if they had to repair ALL the engines this affects) I'm not bitter about this, I love being chumped. So if you haven't replaced all your exhaust studs, go speak with your dealer, he'll be happy to rape...er help you.