Thanks for the advice, I will try to do what you told me to, the reason why I think I have a vacuum leak is that I have a P0171 code that has been present for a long time now, I haven't done any tests myself but I took it to a mechanic and he found and fixed many small leaks on the most obvious areas like air hoses, it did improve but that didn't fix the problem completely, he replaced the EGR valve per my request because long time ago someone else told me that the EGR valve was due for replacement because it was causing the truck to misfire and I disregarded it at first due to the cost ( it's a pain in the neck to get to the EGR in this specific engine) but I thought this time it could make a difference, well that didn't work either, the code is still there plus now I am getting code P0400 system flow malfunction.
Long story short I am just trying to learn a little bit about these codes and maybe diagnose it myself, the truck works pretty well, and still misfires (specially in first gear) but not as bad as before and I drive it daily but I've spent a fortune already and I can't believe the mechanic can't find what the problem is.
Thanks I will look to the diagram under the hood.
Friday, November 22nd, 2019 AT 6:46 AM