Basically two things are happening when the crossover is plugged. The lack of heat causes the choke to stay on and not open properly. Along with the electric assist not working properly. The second is the hesitation. The intake needs to heat up for proper fuel mix. As designed the cold dense fuel mix will cause a hesitation. Where the proper heated mix will not. With this plugged you could easily lose 4 mpg or more along with the hesitation. Most all that we have done include replacing valve seals along with the heat passage cleaning. You also need to verify the heat riser is working properly if equipped. If you do the needed repairs there is no reason that you cant get 18 to 20 mpg at sensible highway speeds.

Blocking off the passage is a performance mod and thats a totally different set up.