Hello,

Besides the occasional backfire (mostly on decel) the car runs great.
It seems that I have to reset the idlespeed on my car each spring and each fall. Which is totally acceptable.

But within the last week it developed a condition where the engine speeds-up between gear shifts. Its almost like Im keeping the accelerator down.

When coming to a full stop, it takes about 3 seconds before it falls down to idlespeed.

It has Dual EMPI Carbs.

What could cause this?

Your accelerator cable is wrapped around your clutch cable

Or cable need replacement or need extra spring return by the linkage.

My Dells did the same thing after about 3k from overhaul. Put some silicone lube on the bellcrank's and on the linkage and it's back to normal. Hope that helps,

I agree with the above possible causes. Disconnect the cable at the carbs to see if the carb linkage or the cable is the problem. If the cabkes are crossed the clutch cable will drag against the accelerator cable. Remove the cover at the front of the tunnel as use a mirror and light to look inside.

Are you using an additional spring on the linkage or relying on the springs on the carb shafts?

There is an additional spring between the Hexbar and engine bay. When operated by hand (turn hexbar directly) it snaps back without delay or drag, but still has the 3 second delay in returning back to idle-speed.

Intake leak

The bracket that holds the outer sleeve of the accelerator cable had shifted, which caused the cable to bind. Problem solved.

Thanks to all that chimed in.

well said,a slow drop to idle is generally that issue,FI is worse but carbs will suffer "false air" issues also been there.
Common area's is that folks overtighten manifold to head bolts and they happly pull out if the head,oh and don't use the crap thick gaskets supply by the likes of EMPI for there less than great manifolds.
Has the OP rebuilt his pedal assembly,is the throttle sticking @ this point or a bad cable...who knows.

can you share how you solved it? thank you!

See picture.
The bracket (red arrow) had moved a little. This caused the cable to bind.
I repositioned it back to we’re it belongs and tightened the bolt (yellow arrow).

Reset the idle speed to as low as possible (approx 900 rpm).

And Whalla.... Problem solved.
Click to view attachment

Thank you! This thread will help some members too. Sometimes we try to find various fixes but ended up just a small issue.

Excellent result and easy,well done .