I recently installed an Accufab Plenum & 75mm TB on my 04 GT. As with everyone else that has done this, I wound up with a "floating" idle.
Since this seems to be so common, I have come to the conclusion that Accufab isn't making the plenum correctly. I believe the bolt holes for the TPS are rotated clockwise from the factory plenum some small fraction of a degree. This is enough to raise the voltage into the 1.3 range (at least that's what mine was) which is causing the idle problem.
I solved my problem by using a suggestion I found on another site. I was unable to rotate the switch enough (counterclockwise) to get the difference in voltage that I needed. I then used a 7/32" drill bit chucked into my tap wrench (my dewalt drill bits have a flat spot on the shank which allowed for this) and hand drilled the holes in the TPS. This allowed enough play to rotate the TPS and get the voltage down to .98. My idle is fine now and no longer hangs.
If anyone here has an inside ear at Accufab, you might suggest that they look into their design. Since it is so common, there has to be a difference in bolt hole location.
This is just one engineer's opinion though.
Hopefully this'll help out anyone with the same frustrating issue!
Since this seems to be so common, I have come to the conclusion that Accufab isn't making the plenum correctly. I believe the bolt holes for the TPS are rotated clockwise from the factory plenum some small fraction of a degree. This is enough to raise the voltage into the 1.3 range (at least that's what mine was) which is causing the idle problem.
I solved my problem by using a suggestion I found on another site. I was unable to rotate the switch enough (counterclockwise) to get the difference in voltage that I needed. I then used a 7/32" drill bit chucked into my tap wrench (my dewalt drill bits have a flat spot on the shank which allowed for this) and hand drilled the holes in the TPS. This allowed enough play to rotate the TPS and get the voltage down to .98. My idle is fine now and no longer hangs.
If anyone here has an inside ear at Accufab, you might suggest that they look into their design. Since it is so common, there has to be a difference in bolt hole location.
This is just one engineer's opinion though.
Hopefully this'll help out anyone with the same frustrating issue!