Rattling Sound

[ricklee4570]

1994, when going up a hill it slightly rattles. Im thinking it is not detonation, because when it downshifts (automatic tranny) the rpm's go up to about 2700 rpm, the sound does not change. When it shifts back to O.D. the rpm's drop to about 1500 and it is the exact same sound. On level ground it stops. usually detonation will cease when you downshift to higher rpms and are not lugging the engine.

Thanks!

 

[mawrazen]

May need a better description. How is your fuel economy? Any black smoke?

 

[ricklee4570]

No smoke, fuel economy is decent