I had a simlar problem with my 95 contour. When I put the car in gear it would almost stall. Finally someone told me to take off the mass air flow sensor and clean it. worked well. give it a try.
When i sit in one place while holding the brake, my car starts to shake really bad
1999 Contour SE 2.0L VCT Mods: *BFGoodrich P195/65R14 *Pioneer 3100 Cd player *Pioneer 6'x8' 3-ways *2 12' Super Blue Subs *Pyramid 400 Watt Amp *Yellow Fog Lights *Magnaflow Exhaust #14822