1994 Chevy Camaro Idle problem

Engine problem
1994 Chevy Camaro 6 cyl Wheel Drive Type unknown Automatic 161773 miles

when the weather is cold, I'll crank the car, it holds an idle for a moment, then it dies...I have to hold the gas pedal til it warms up a bit, then it will be fine. I have replaced the TPS and that fixed the original problem of not holding an idle at all...In recent weeks I have also replaced the egr valve, a bad coil, crank shaft posit. sensor, fuel filter......I took my car to a mechanic and he hooked up the computer..he said the egr valve was bad....I have spent more money than I care on bad advise....an auto zone employee was of bigger help as he suggested the throttle posit. sensor....that at least help a great bit....can you please help me? Thank you Trish