I did that IAC mod and was wondering if it lowers your gas mileage. It might just be in my head, but it seems like I've been going to go through more gas with the new gasket. Does that just come with the disadvantages? It also seems to make this gurgle noise when slowing down in gear.

 

The gurgle is normal...

The gas mileage (so I'm told) is not normal, but I experience it too. I went from 19mpg to about 16mpg just with this mod alone. I can't explain it, but I think it has to do with the richer mixture when dropping revs. More gas goes out the tailpipes because of the less airflow when returning to idle. Thats my guess.

 

So did you just take it off, change it, or just leave it?

 

Does anyone else have this problem?

 

I've been using one on a 5-speed Mach 1 for three years with absolutely no drop in gas mileage after installing it.

 

I've got 17k miles on my custom mod (an aluminum restrictor plug in the IAC inlet hose--see below) and have had no problems of any kind. The revs drop much faster between shifts, accompanied by a nice carburetor-like exhaust burble, and the idle is rock steady at 700 rpm.[/align][/align]Youshould reset the computer's adaptive memory (the KAM, Keep Alive Memory) after this or any TB/plenum/IAC/EGR mod--it appears that many are not aware of this and this could explain the poor idle and perhaps poor fuel economy same have reported. I get a solid 22.5-23.0 mpg on my 100 mile daily commute; with 3.73 gears and at 80-85 mph, andwith one or two 95-110 mph "sprints" while passing a string of semi-trailers not being a rare thing...[/align][/align][/align]