I have a 1999 Chevy 4x4 pickup ...half ton... 350 vortec. i started driving fine but when started to get on the free way.. i could not go past 50mph then started to get worse and cant go past 30mph now. and had the gas peddle on the floor and felt like i was pulling a semi. then spent $1200.00 to fix it, they replaced the fuel filter,o2 sensor, cat converter, but it is still doing the same thing.. does any one know the problem. please help...

 

Not totally sure, buy sounds like your ERG. My boss had the same issues, worked like a charm after he replaced that baby