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Mystery vacuum leak?

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1978 280z L28. Full emissions delete. 


So she was running great and strong. Drove the car all day. On my way home, I had a little fun. Opened her up a little. She pulled nicely. Then I turned a corner and the car got rough and I had to shut it down. I had to tighten up the AFM quite a bit to the lean side to get her to run again. So my assumption is a vacuum leak. The problem is that I can not find it. 


I have all new vacuum lines and all extra ports are capped off. I inspected all lines and caps in good shape. I then went with a can of carb cleaner around the intake to try and get a rise, with no effect. Also checked timing again. Solid @ 11 degrees. Fuel pressure around 36-38psi. 


All symptoms point to a vacuum leak but for the life of me I just can't find the source. She was running great. And then not. No immediate signs of the problem. Just the symptoms. The only vacuum lines I have are brake booster, dist vac advice, charcoal canister, FPR and pcv valve if you want to call that a vacuum. 


All thoughts and suggestions are welcome as always. And thank you in advance. 

Edited by Mike33Stig
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So I found the problem while going over the vacuumal lines again. It was a bad connection to the temperature sensor causing the motor to run very rich. Cleaned and tightened up the connection and all is well again. 


@NewZed Thank you once again. It was just luck i found this bad connection when i bumped the harness in the area. 

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