my freind has an 05 impala with 185000 mi new plugs and wires 2 months ago new fuel pump 1 week ago. starts hard when cold ok when hot.

what does the air filter look like ? you might also need to clean the carbon off the pintle for the IAC. Clean the Throttle body with sensor safe cleaner.
Has the computer thrown any codes. Check your PCV valve, get a new one they are only $3.