2002 Mitsubishi Diamante

sunny07

I could be driving down the hwy and then I slow down if I hit the gas to speed up it Nothing I really need to find out what's wrong with it 

sunny07

And it dose Not kill I'll have to let it coast before it picks back up 

Mr_Shiftright

So, kind of a "dead pedal" feel? You might cruise YouTube to see how to clean MAF sensor and throttle body (these require different solvents and procedures). Just a guess of course. Getting the car scanned for codes would help.