A while back my truck had code P0401, insufficient EGR flow. I cleaned the EGR valve, tube & all vacuum lines. I had no vacuum, Recently I got the same code. I followed the same steps as before. I now have vacuum but the truck loaps really bad with line connected to the EGR valve. If I disconnect the EGR valve vacuum line, the truck seems to idle a little better. Can anyone make any suggestions as to what could be causing this ?