[T3] Engine Idle very low, once warmed up

[Jared Kohler]

Hello All!

It's been a while since I've reached out to this list! I enjoy reading almost every email and the information has helped me continue to keep our 1970 Fastback with FI alive as a daily driver.
Now, I have a question for you all...Our Fasty has always had a super low idle issue once she has been driven some and the engine warmed up well. After a drive around town, the idle drops quite low. She'll run, but always seems on the verge of sputtering-out. Again, always when the engine is nice and warmed up. First starts in the mornings or after parked for a spell and a decent drive around town, she acts wonderfully, but continue to drive, engine good and warm/hot, come to a stop sign, idle has dropped super super low. What's happening here?
This issue has just been something we've lived with since as long as we keep the engine RPM up a tad, we can keep cruising around town doing our thing. Doesn't miss-fire, doesn't hesitate, but take you foot out of it and come to an idle and boy, the engine idle is low.
Little History: I installed the engine, which was pulled from a 71 Square with AT. Our Fasty is a MT car. PO had installed a Type 1 upright 1600 in the car because he didn't have the patience to service the original FI ENGINE. I bought the Bentley book and figured out the FI in a couple weekends. Thus, our lovely FI set-up now, yet what have I missed with this idle issue once engine has warmed?? Oil temp vacuum sensor? 

Ideas? Thoughts? Past experiences?

Your experience and mechanical savvy is greatly appreciated.

Jared Kohler
Goleta, CA


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