EGR Issue
#11
It's obviously opening and working or the problems wouldn't go away with the vacuum line plugged.
Most exhaust shops can check the back pressure. They drill a small hole in the pipe ahead of the converter and check the pressure with a gauge. Then weld up the hole when done. Many do it for free.
Most exhaust shops can check the back pressure. They drill a small hole in the pipe ahead of the converter and check the pressure with a gauge. Then weld up the hole when done. Many do it for free.
#12