My 01 Windstar makes a weird noise when going up incline or when more power is needed on roadways. Its hard to describe but its almost like a " shaking rocks in a can" noise and I experience a slight loss of power.

I already preformed the 3-16-01 TSB (P0174, P0171) on it but the noise did not go away.

I am about to start putting a different octane in the tank but besides that does any one have any suggestions on where to start and what it sounds like?

Thanks again guys,

Carlos

It's likely "pinging". Some good reading here: http://en.wikipedia.org/wiki/Pinging

My Windstar did this when the isolator bolts needed replacement (I never did get the infamous P0174/P0171 codes). In my case, the isolator bolts were allowing just enough air leakage to cause pinging. Did your TSB fix include replacing all the isolator bolts and port seals?

A quick test: Add a can of octane booster to the tank (a typical auto parts store will carry it). If the pinging immediately stops, I suspect you've still got an air leak in the intake somewhere.