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Discussion Starter #1
I've noticed today after starting my car that it takes awhile for the idle to come back to normal. It's a 350-300hp with the TH350 trans.

I hit the pedal, and the engine responds fast, but when it returns to idle, it seems to take awhile for it to come down to normal.

I checked around the engine, and I don't hear any hissing of vacuum, but I'm still thinking vacuum leak..

Any suggestions???

Thanks....
 

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Throttle linkage or pedal needing lubed?
Throttle return spring weak?
Primary throttle shaft being pulled to the side of the playe and when it retuns to idle, the butterflies rub against the side of the bore?

Spray the throttle shafts with WD40, ATF, or squirt with oil can to listen for a change in rpm.
 

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Make sure your distributor advance weghts are not sticking.
 

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If this problem just appeared with the arrival of cold weather, your choke may need to be adjusted. For example, on my 67 Chevelees SS, I find that when I ride down the highway on a cold day, the air flow is cold enough to re-engage the choke, but once I am back in stop and go mode, the choke will pull off again. I am tweaking to get it right ( works fine in warmer weather ). My canister is riveted in a fix position, so it has taken me awhile to figure out how to adjust it. Anyway, you may need to just back off your choke just a little. In warmer weather, we sometimes adjust it to stay engaged a little longer, but in cold weather, the air temp will extend the time it stays engaged. If the slow throttle release happens on a warm, idleing car, then yeah, back to the previous posts ...
 

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Choke issue if it only does it when cold.

If it does this all the time, then check to make sure carb secondary butterflies are adjusted properly. On Holley carbs there is an adjustment for them.

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Discussion Starter #7
Found the problem......

I was checking it yesterday, and I noticed when the idle was staying "high", I pinched-off the hose going to the pcv valve and the idle went right down to normal.....

Now I'm guessing that I have the wrong PCV...

Which is the correct AC Delco P/N for a 69 SS350/300hp engine????

Is it a CV736C or CV746C???

Thanks...........
 
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