1990 f-150 just put all new parts in the ac and wanted to know what readings should I have?I used envirosafe instead of the r-12.

 

According to my book 25-50 low side and 160-250 on the high side. Those numbers assume R-12, I have no idea how the drop in replacement affects pressures.

 

Ok I did some quick research on the Envirosafe and the pressures are about the same. They claim that the high side could run about 15 lbs lower.

Your truck used 3.25 pounds of R-12 originally and the Envirosafe says to use only 1/3 of that or 15.6 oz. Were it me I would vac it down and put in the recommended 15.6 and see what happens. Let me know how the Envirosafe works if you would.