Ford Motor Company vehicles should operate normally if the customer uses blends that contain no more than 10% ethanol or a blend that contains no more than 5% methanol with its necessary co-solvents and additives. If the methanol does not contain the necessary co-solvents & additives, it will damage the vehicle.


Gentlemen I would like as many opinions as possible on this subject.

I bought new a 99' E-250, From day one it had an engine noise that sounded like rods rattling or a chain rattling from the engine. It became louder as the engine became older it currently has 80,000 miles.

To date I have spent a small fortune trying to find the cause.

New Mass air flow,cleaned injectors,New intake manifold gasket,plugs,egr parts ,new computer,upgrade software,all new 02 sensors, coils,

Experts have said, standard engine noise,to piston slap.

I just started using 89 octane with 10% Ethanol and the noise completely went away. I am on my 3rd tank with no noise at all. before this I was afraid the engine was going to blow, the noise was getting really bad.

A mechanic said for $1000 He would replace my brake booster which has a vacuum leak per code this would also rid the engine of it,s noise.


Could it be the vacuum leak had the computer adjusted to max and I was getting a poor burn, which the higher octane now has a hotter burn bringing it back closer to normal? just a theory?



any thoughts please.