The engine had been burning coolant out the tailpipes, so i took the heads off and replaced the head gaskets, when i went to start it up the first time, it didn't do anything, no fuel pump, no check engine light, no security light - nothing. When i turned the key to "start" the temp gauge would rise. So i'm sitting in the car kinda ticked off and i started fiddling with the climate control lever and everything lights up like normal and the car starts. If i turn the ac off, the engine will cut out. And now when I rev it around 3k and above, the check engine light flickers, and it sometimes flicks on for a second or two when its idling and when it does the engine stumbles. The tach periodically "jumps" also. Its a 91 with a 305 tbi with about 221k miles on it. Any ideas what the problem might be? Bad ecm? bad connection somewhere? ???

 

Did you replace the ground strap on the back of the passenger side head to the firewall? Was the starter taken off and not all of the fusible links put back? It's backfeeding through the A/C system somehow.

 

The wire on the head was loose, so i tightened it and it starts now, but it still has the other issues, and i noticed a pulsing at the tailpipe ends, it seems to go between vacuum and pressure - as my hand almost acted as a reed valve. There is also a chhhht noise coming from the drivers side header (and a similar noise from me). Is this a sticking valve or something similar?

 

Descriptions of noises are always fun to read. Is it like a buildup of pressure ? Do you still have a cat on it? Possibly it's clogged and causing extreme backpressure. The pulsing could be valves to tight. It is often a sign of a burnt valve but you just had the heads off so I assume you had them checked out or at least were up close and personal enough to see if this was the case.