1995 Mitsubishi Mirage computer scaning cdes

Engine Performance problem
1995 Mitsubishi Mirage 4 cyl Automatic 90000 miles

hi, I scanned my car and it shows codes 32 manifold absolute pressure sensor, code 43 egr system problems and code 55 iac valve position sensor. My question is, What part I need to buy, since they are electrical parts and there is a not returning policy on them at my local store. Where I can find a list of codes relations toward part numbers?
tks, rafael