My 95 z when you first start it up idles fine and revs nicely, then right when it goes into closed loop on the scanner after warming up, it will barely stay running and if you give it any sort of throttle it just completely falls on its face, and ideas on what could be causing this type of situation, Thanks for your help, Paul

 

Sounds very much like the gremlin my son has been chasing, also a '95 'Z".

 

Yeah I'm stumped, I've tried new coil, icm, opti and it still does it. I'm hoping someone has some sort of idea. Thanks, Paul

 

Jeff has also replaced the O2 sensors, Did some adjusting on the TPS, Replaced the EGR valve (Got a code for EGR but it made no difference). I think he has replace all the sensors within the last few months. So, it's not a sensor OR he bought a bad one out of the box. He has replaced all the vac lines too.

 

This is a guess, but check for exhaust leaks.

It would be really helpful to everyone trying to help you if you would make a signature saying everything you have done, so we can narrow it down a bit more .
If you need an example you can look at mine.

 

Mine is a 95 z all stock, bought it with a blown engine put a 93 bottom end with the 95 top end on it, and it has a 3 inch cat back and that is all.

 

If you take the time to set up a "signature", you won't have to type that every time you post a question.

 

It is either the O2 sensors or the wiring going to the sensors. When the system goes into "closed loop" the PCM is getting its information for fuel from the O2 sensors. I had some wires going to the O2 sensors get too close to the headers and melt together and it acted much like you are describing.

 

post the blm's (Long Term Fuel Trim) values at startup and what they do when the loop closes

same with the integrators (short term fuel trims)

Bob