Partial throttle issue

[Double D]

I've noticed this with my turbo setup and now a friend just came to me with a very similar issue on his supercharger setup so I'm curious if maybe we've both over-looked something simple.

Has anyone had any issues with there setups not wanting to maintain a cruising speed (~35-45 mph) at partial throttle? I'm not sure which way to go to try to clear this up so some insight from others would be nice.

I have no issues accelerating, whether it be WOT or partial, as long as there's a load on the motor it pulls fine. As soon as I pull out of the throttle to the point where the motor isn't under load, that's when it acts up and my power seems to be intermittent. It'll maintain power for a short period (couple seconds max) and then cut out, and then the power comes back.

I kinda feel like this may be vacuum related somehow but I'm not sure. If need be I can detail out my setup but I'm pretty certain under a light load like this it shouldn't be fuel related.

 

[2slo4u]

has it been properly tuned?

 

[Double D]

I'm tuning it myself. I've got my fuel map set and going to start into ignition timing. Really, I'm looking for someone else who has done their own tune who might be able to give me some pointers.

To me it almost seems like the throttle plate is just being pushed closed at partial throttle and that's whats causing fluctuating power. That's why I was thinking maybe it was vacuum related somehow. Like if I might need to do something with the IACV or even the throttle plate itself. Now that I think of it, I wonder if it could just be the throttle cable being a little loose.