93 ,3.4 auto ,can someone please help here,,my camaro will run fine in open loop operation,and run like crap in closed loop,ive replaced all sensors already,no codes when scanned,,replaced map,ect,o2,iat,cam and both crank sensors,replace ecm,new cat installed,new plugs and wires,,new icm and coil packs,new egr valve,fuel pressure check is good,,compression is good,,whats left???,,i have no idea,,no dtc found when scanned

 

Sheesh, are you done blindly throwing parts at it yet? Without getting an error code, how do you even know it's an open/closed loop issue? It might be related to the engine heating up in general, such as...could be an intake manifold gasket that's just barely hanging on with a cold engine, and after the manifold gets hot, it warps just slightly, but enough to open the gasket seal. Had it happen before, and you won't necessarily develop a coolant leak either. Could also be an ignition module or coil (although I see you replaced the pack) that craps out when it gets hot, had that happen too.

 

ok,,here's why i know its a open/closed issue,,i can unplug o2 sensor to keep it in open loop and car runs good,,no miss or nothing i can leave it like that and it drive it alll day long without a problem whatso ever it just don't have the power like it should when in closed loop,it only misses and stumbles in closed loop,,if it were a intake issue or ignition wouldn't it do it all the time ??

 

Yes, if it was the intake gasket or ignition causing it, unplugging the oxy sensor wouldn't straighten it out. Gotta put thinking cap back on!

 

Gee, the only things you didn't mention is the O2 sensors. Look at the sensor output with a scanner, the voltage should be going up & down at rapid rate. If the voltage is steady, the sensor is bad. Those old ECMs did not report all O2 sensor problems, except if the O2 totally failed.

 

^ Actually he did Pete.
But, he hasn't replaced the engine....yet!

 

any more ideas here,,could i have a injector problem??,,tested with noid light all is fine,but someone said a injector could be stuck,,but i don't know because it runs good while in open loop

 

check and clean all your grounds. test the evap system and gas cap.

 

Before you replace the engine, get a OBDI scanner, not a code reader, then look at the output of each sensor and verify that they make sense, like the temp sensor when the engine is cold should be close to outside temp, etc.. The FSM has a list of what the ECM should see from each sesor.