emsvitil, what header do you have? I seems reasonable that something like the LCE, where the EGR notch may be too small, requires a bit of extra backpressure to force exhaust gasses through there. I thought since mine killed the motor so easily at idle that it would be fine at speed without a baffle. My reasoning was at idle there would be the least amount of pressure from exhaust, compared to 3000 rpm and up, where the EGR system is supposed to kick in.

Don't have a header.     I've contemplated buying/making one (I went as far as buying the exhaust flange).      So I wanted to know how the EGR system worked because I was always just squeaking thru on the smog test with just a cat-back exhaust system.

CA actually made it harder (lower threshold) the same year I first put the restrictor in the exhaust (I would have failed with my historic readings with NOx).

Note:  the squeaking thru was just with the NOx...........