really need some help

a friend of mine has a 95 camaro 3.4 V6 auto. the problem is when it warms up it dies. it starts right up but dies again. it idle erratic. it will idle up then down 2 or 3 time then dies. it started about 3 weeks ago so far we have changed the MAP sensor, idle air control valve, pcv valve, air filter and fuel filter and have tested throttle position sensor, battery, alternator and the Air Charge Sensor. all the vacuum lines seem to be good with no leaks. spark plugs look good and wires look fine. took the car to autozone to have them check for codes but there was none. the only thing that we can think of that is left is the EGR valve. any help at this point would be great.

Check fuel pressure. Does the fuel pump whine?

my friend said he checked it.. said it was where the book said it needed to be at. as for the fuel pump it does not whine.

after replacing all the stuff i have listed plus some there seems to be oil in the radiator (friend didn't check this first) after the car has been running it starts smoking from the back of the motor. not sure where the smoke is comming from. anyone have any idea what is going on? please help

If it is oil in coolant, one reason could be cracked head or block. Intake or head gaskets usually will leak coolant into oil pan. It is a matter of pressure differentials. What color is the smoke? Does it smell sweet like coolant?

it didn't reall have a sweet smell and the smoke was white

Sounds like a blown head gasket to me.

Ok So Say It Is A Blown Head Gasket. Does Anyone Know How Much A Shop Will Charge To Do This And How Can I Be Sure It's The Head Gasket.

Head gasket? How much? I don't know. You could call a shop and maybe get a ballpark est. It won't be cheap.
Some ways to tell without special equipment. Do you go through coolant? Does it overheat? (if it could run long enough) You could try pulling sparkplugs and see if they are all colored the same or if some look different. A shop could tell by using the emission probe. If it is inserted in the radiator and it reads HC in the coolant while it is running as the result of a leak.

the coolant is fine there doesn't seem to be any coolant in the oil and the car doesn't overheat. i called a shop down the road from my house the guy said the only way to tell is taring down the motor and that would cost $300 to $800. or maybe more. he said it would be best if i just got a new motor.