73 Duster, mild '70 340. I've run a ThermoQuad on it that DemonSizzler originally set up for my failed 408 stroker. I've had no problems with idle or anything until recently. Car runs and drive great except when i pull up to a light...foot off the gas it idles but seems to cut out or drop out every 5 seconds or so....kinda makes the whole car hesitate for a second and makes you think "if it keeps doing this, it'll die"

It hasn't yet but somethings making me think the carb is loading up or something.

I thought about leaning it in some with the screws and at one point decided to run them in completely...I noticed this did NOT kill the motor..that made me think it's the carb as well.

Timing checked out good at 8 degrees advance and it's solid too. the motor has under 1,000 miles since the rebuild.

Any ideas on this?

T-Q's are good for a bad needle/seat inlet occasionally.

If you can run the idle mixture screws in completly at idle speed, then you have a vacuum leak somewhere, try changing the gasket.

Another common problem, especially if the carb ran good and the trouble suddenly occurred on it's own with no other changes is fuel contamination. Was your entire fuel system new/fresh from the tank forward when you installed the carb? If not some junk likely made it's way into your fresh carb, sometimes it doesn't take much to cause the issues you described.

Sounds like trash in the carb, possibly in the IFRs or a bad vacuum leak, but i'm sure its minor either way.

i have a new tank, unit, and the lines were cleaned out over a year ago. I'll take it off and give it a good cleaning along with the other suggestions..thanks!

Check the total timing. Run the engine to 3500 rpm and read timing. It should be about 32 with vacuum adv unhooked.If you do not have a dial back timinglight then Set timing at 18 degrees at idle, go drive it and see if it is better.

On my wagon, when it was my everyday driver, I kept having a problem of the mounting bolts for the carb (TQ) working loose (heat cycling and plain ol' vibration was my guess). Car would be running fine, then one day, the idle would be a little funky. Nothing severe, just enough to get your attention.

And, yes, I tried thread lock, but, I still had the problem.

I just got used to checking the bolts on a regular basis.

(if it matters, I'm running a stock intake).