Ok, i have a 1990 F250 w/460. My check engine light is coming on/off all the time now. Seems the more i drive it, the more it stays on, until i get on the freeway. I pulled the codes and it gave me the EGR Valve. The thing is, I replaced the EGR Valve about 8 months ago? I also checked the lines, none of them are broken or cracked. Any suggestions??

 

i would check for a clog somewhere, if your sure the valve is good.

 

where/how do u check for a clog?