marovetsm

iTrader: (24)

Normal Idle is fine but when I come to a stop sign and step the clutch in the idle dips way down (sometimes dies) then jumps up to almost 2000rpm somtimes then dips again and it almost always does it 3 times before it settles back out and idles normal. This is extremely annoying, especially in parking lots.

Had the truck tuned at a shop twice and its been like this after both times and its really a pain. I want to try to fix it myself, Im new to tuning to so Im still reading/learning. Thought I would ask because maybe this is a simple fix that someone has run into before.

Ive run the idle-airflow, and adjusted idle underspeed spark both with no improvements.

Truck mods: 4.8 Radix 112, 70lb injectors, E85, LT's, 217/219 cam.

Here's a clip of it, this time it wasnt bad, its usually much worse but it gives you an idea of whats happening. Attached is the tune as it came from the shop, not my modified idle air and spark file. (since it didnt help).

‪Idle dip‬‏ - YouTube

marovetsm

iTrader: (24)

Heres a few scans. And one where it actually dies.

MikeGyver

iTrader: (5)

Make your high octane, low octane, and idle advance tables all the same in the areas that the engine actually idles. The areas that it idles in rpm and air flow from a log. Then blend the transitions in each table. Report back after that.
It's weird, to me anyway, the way the idle tables are at zero at higher air flows.

Gadgetized

iTrader: (9)

I am not familiar with HPT, but in EFILive, that can be corrected by desired airflow, or by throttle cracker. It looks like you need to increase the airflow. It appears to be set too low, making it fall on its face, or stumble. Then it is over correcting, making it rev up. I had a problem with this too, but it is now better. Does it do this only when rolling (like over 10 MPH or so)? If so, then it was throttle cracker on EFIlive. I would assume it would be something similar on HPT.