Hey i have a 99 corvette ls1 coupe..ok and im having a problem with it. ok it started about a month ago. at first the motor would shake around about 70mph, like it was kinda misfiring or something. and then it stops for a day or so. ok its been a month since it started and now it does it at low speed and high speed. but it comes and goes, sometimes it will do it and sometimes it wont..so i changed the plugs and wires and it still does it just as bad if not sometimes worst. does anyone know would it could be or what i can do to fix it.

 

try changin the fuel filter man. Maybe some fuel injector cleaner would work too. oh and seafoam works wonders

 

Is it throwing a Service engine soon light?? Does the idle go up and down when idleing??

 

Sounds like it could be an EGR valve going bad.....but who knows??

 

it could be a lot of things... your just gonna have to take them on one at a time until you figure it out, or take it to a shop and let them deal with the head ache