Will not hold speed

94 metro 4 dr. 3 cyl. Auto; It does everything OK but when I accelerate lets say to 30, 40, or 50 MPH and I finally reach that speed and try to cruise and let off the accelerator to maintain a steady speed, every now and then the engine does as if I had let the accelerator completely off and slows down, then it picks up again as it was before. It does it so rapidily that sometimes its hard to notice and sometimes its very obviuos. It does it at any speed but it doens't do it while accelerating. Sometimes it even does it while idling for a long time.
Any ideas ?
Thanks to all.
:banghead:

Sounds like your throttle postition sensor is outta wack.

My vote is for the TPS as well....just got done replacing mine....sounds like the same issues I was having to deal with. Easy enough job, but cost me $120 in parts...discounted....hopefully not as expensive for you ;)