Hey all been a wile since Iposted and hope you are all doing good with your trucks as the warm weather comes.

I have been haveing an Idle probem for the past few moths and i have been puting it off because of the cold in new england and the fact that i wasnt using the truck much, but now that i am employed again id like her to runa bit better. So you all know I have replaced the MAP IAC and TPS but i think i have stumbled on to something. Now I have 1990 XLT with a 5.8w, on the throttle body there is a vacum line on the left side (looking at motor from front of truck) this vacum line comes out about 3 inches and goes into what appears to be a one way valve,this valve has an electrical cylender on it and hooks up tot he same harness that the TPS and EGR hooks up to. after the valve it goes into a plastic box inbetween the radiator and battery on the pasanger side of the truck. What is this valve called? i belive it is blocked or broken because when i disconnect it the motor's idle straitens out some, and it could hurt to change becuase its an original part.

Thanksin advance to anyone that can help

EDIT Not sure if this is anything but i saw ony one of my diagrams something called a CPRV is that what this is? Anyone know were to get a good ford Vacuum diagram for a 90 5.8 also?

 

I think you are talking about the EVR which is a filter, it bleeds off the engine vacuum that operates the EGR valve and if pluged up can cause bad engine idel. just take it apart and clean the filter with soap and water and reinstall and your idel should be better.

 

Nope, that's the canister purge solenoid. It opens up to allow the vapors from the carbon canister into the intake stream. I have no idea how to test it, and I don't have my service DVD with me right now.