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Well here is the verdict.. don't know if any of you read banter and chat but i really discussed this on there. Heard back from teh mechanic after two weeks of testing. They have checked every connection, bolt, sensor and hose in the engine an cannot find out why the car runs fine until it starts to warm. And then when it runs half the time it runs like its about to die and then he other half it runs great until it starts getting to about 140 degrees and then WHAM.. Putter putter cough die.. I trust the guys at the shop because several own z's and their are several shops around and the guys have never failed to fix it yet. this is a first. So any ideas guys? I exhausted all my options before i took it in trying to fix it myself. No vacuum leaks.. The connections are all good and clean and lubed with Dielectric grease. So far as i can tell it should run like a scalded monkey. I dunno. only other thing i didn't test because i don't know how outside of getting another one is the ECU. Maybe its heating up and causing a problem when it heats up by breaking connection. Any ideas guys?
 

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Hi Stephen.
Welcome to fuel injected Z ****. This is a common problem with worn and high milage Z cars. It runs great until you stop and turn off the ignition for a few miniutes to run into a store or someplace and then....nothing....cough,sputter,sputter,cough. Wait 5 minutes for all to cool down and Verooom it alive again. What happens is the electrical resistence at the injectors drops to ZERO and the negative connection circuit goes invisible as though it does not exist. Many of the later model ZX's with the L 2.8 engine addressed this with an electrical cooling air blower that after engine is turned off will come on until manifold temperature drops and heat at the injectors has cooled. You COULD adapt this as an alternate to your 78 engine, linking the positive wires for the blower to a rocker switch and fuse from the battery or you could do what I did when my 77 road Z, my number One baby began exhibting that behavior: Replace Oil Pressure Spring at the Oil Filter. Inspect and Clean all Grounds to the Injectors, even going as far as to adding additional Grounds at engine and chassis points for the Injector negatives.Clean your throttle body of anything that looks black so once more its nice shinnie metal inside. Pull your Cylinder Head and Clean your pistons of all the carbor crap thats stuck there like glue preventing air flow to escape as the exhaust valves open thereby preventing combustion at the cylinders. Replace your fuel and air and oil filters. These are what worked for me. I have NEVER experienced this particular problem with my 77road Z again. So your Z wrenchs can 'work' on your baby's problem or you can/should take it to somewhere/someone who can FIX your baby's problem. My solution is simple and should you be doing the work your self then very cheap. Costs of new cylinder Head gasket and Intake/Ehaust manifold gaskets. Maybe 30dollars. Goodluck. shane-
 

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Perhaps put a fuel pressure gage in line at filter and see what the pressure is doing at the time it starts to sputter and die. Other than that it almost sounds like a temp SWITCH was installed in place of the coolant temp sensor. 140 isn't really high enough to cause any fuel problems in the injectors. That was more heat soak related. That temp is also around the temp where the egr is supposed to start working. perhaps there is an open egr valve or some vac line mis routed in that area. If the BPT were bypassed or stuck open, that would route vac to the egr valve when the TVV opend up at around that temp.
 
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