I'm getting code 558 - eletrical circuit of EVR, continuous code 334 - electronic vac regulator, and code 565 - cannister purge solonoid.

I have 12 volts to the EVR. Is there a way to test the solonoid itself?

I have vacuum tested the cannister purge solonoid and it appears to be good.

Any experience with these issues is appreciated.

Truck (1995 5.0 EFI) starts and idles but craps out under load.

 

check your lines st back side of heads for leaks damn emissions problem i bet the efi lines (vac lines) all tye in with the smog pump lines.

 

558-EVR circuit failure. The EVR should have between 20 and 70 ohms resistance on the solenoid. If you have voltage and you are good on the Ohms, you should check your vacuum lines like Dragonhunter said. But I think since you have two cicuit failure codes, your problem may be electrical.

334 is EGR closed voltage higher than expected. Means either your EGR isn't closing all the way, the EGR position sensor is out of range (bad).

565 cannister purge solenoid cicuit failure. I believe this means the solenoid is bad and the circuit is open (solenoid coils burned out). There is not a lot of technology involved in the evaporative system. Just an electric valve in line with the vacuum line fom the cannister. I assume the ecu is not getting a voltage signal from the solenoid. You can test the Ohms of the coil.

Hope this helps

 

thanks for the help - will let you know.