i bought my camaro about a year ago and immediatly had to pull the motor due to a broken head bolt. I have been driving it for about 10 months now and on the way to work one morning the car lost power and would barely keep up with interstate traffic i trailered it home and here is what i got The car will crank and idle but when you give it gas it will barely accelerate. When turning on the a/c it tries to die. I've replaced fuel pump, fuel pressure regulator, EGR valve, unbolted the catalytic converter (thinking it was clogged), and replaced the ecm with one from the local salvage yard. still cars the same... i tested the voltage to my sensors and i have a ground and the 5v reference but im not getting 12v to a number of sensors. any ideas? Also, is it necessary to flash the ecm even though the service numbers are the same?

 

Have you tested the fuel pressure with a gage?

 

it bounces between 35-37psi

 

Should be between 41-47psi with engine off(key ON) and lines pressurized. Then, when you turn the engine on it should drop somewhere between 3-10psi. Turn the engine off and it should also stay at the same rating, it should not drop psi on shut off.