93 4.3 w ....cruise control prob/mph drop in use

[BlazinUP]

hi all............
iv got a 93 s10 4.3 w motor....with 145k
runs purrrfect........allround.
the funny thing is....when i use the cruise....and set it to 65-70.
it will loose about 10 mph goin up hills.
iv had many cars with cruise and never had one not keep the set speed.
some input would be much appreciated.

thanks

[BlazerLT]

Will it downshift at all?

[BlazinUP]

it does d/s i think ..but,,,,,doesnt seem to be enough unless i help it a lil .seems like i need to give just a lil more throttle to get back to speed.

[BlazerLT]

You think?

[BlazinUP]

it does seem to d/s but not enough to make it accellorate like it would if i step on the gas my self.
it goes up the hills fine...when i dont use the cruise.
thats why im askin for help.
i would think it was the tranny...if it did this while not using cruise.
but again...this only happens while using c/c.

[BlazerLT]

The cruise control i svacuum operated.

Make sure the vacuum lines going to the vacuum ball under the hood are leak free and connected properly.

[BlazinUP]

will do...thanks