[pacey]

Can anyone tell me what the function of the thermal vacum valve is on EFI manifold '80 model???? And do we need it?

Thanks.

 

[johnh240]

The TVV is part of the EGR system. It is one of the items that makes the decision of when the EGR valve should function. You need it to allow the EGR to function correctly. Whether or not you need the EGR system is between you and the government.