Keeping a stady speed, Please Help

Ok here it is i might as well try this too couse god knows i tryed everything els , "The problem i have whit my 1991 Geo metro 1.0 3
is that i cant keep the steady speed if i want to go 55 mph The car starts loosing power and the check engine light starts blinking it wont stay on thats what pisses me off if it stayed on then i can just read the code but it doesnt want to stay on i tryed everything so far took it to couple of mechanics and they dont know what the problem is there anybody that can give me some ideas of what could this problem be thanks alot up front for any help

Sounds like a faulty or mis-aligned throttle position sensor. A Haynes manual will give you the full procedure on re-aligning the TPS.