Pulled Codes from Car, Need Help!

[StreetStang37]

My car has just started to have problems idleing. At a light my car is either on the verge of stalling or idles rough at 900-950rpm (but most of the time it wants to stall). I pulled a 67 and 32 codes. The 67 is about my clutch having to do with the cruise control. The 32 on the other hand has to do with the EVP (EGR Valve Positioning Sensor) having too low of voltage. Where is this sensor? How can I fix it? Is this my problem with the idleing or is this something not to worry about? I NEED HELP! THX.

------------------
1993 Mustang GT - March Ram Air & Pullies, K&N, C&L 73mm MAF, Edelbrock 65mm TB & EGR, 3.73 Gears, 1 5/8in. Super Comp Hooker Equal Length Headers, 2 1/2in. High Flow H-Pipe & 2 1/2in. Flowmaster Cat Back, FlowTech Cut-Outs, Pro 5.0 Shifter, 16* Timing Advance, 8.5mm MSD Super Cunductor Plug Wires, Romoved front Sway Bar, Nitto DragRadial, Pro-Shift Lite, LX lights