I installed a Holley Sniper Stealth EFI in 2020 with my new 383 stroker build. The Shop that did the bulk of the work did an excellent job with the grounding and I have had no issues with Interference or grounding. The system has been great. Recently we replaced the gas tank and after reassembling everything. I had what I think is a TPS failure. I replaced the TPS and everything seemed great for a few days. For over a year, even prior to the tank install I had been experiencing a problem with the idle speed hanging at 2000 RPM when on decel or when I let off the throttle slowly. Blipping the throttle was the cure. After replacing the TPS the problem abated for a few days, and I realized that I really wanted to fix the issue. A lot of research on YouTube and Sniper Forums went through the usual culprits, hanging cable, wrapping the secondary throttle spring, the tune, etc. The IAC was set and performed very well until I accelerated and let off the gas. I found a couple of YouTube videos that indicated all these other fixes were only to symptoms, that the actual problem root was the secondary butterflies working their way to off center in the bores. This could have been due to use, trash, or a number of other probabilities. The fix was to remove the throttlebody, turn it over and loosen the butterflies on the secondary. When loose, rapidly opening and closing the primaries and the secondaries, i.e. allowing them to snap closed while the butterflies were loose (just barely loose), would recenter the blades in the bore and that was the root of the problem.

When I got the throttlebody off, I noticed a lot of residues built up on the bottom of the blades and the bore. I exercised the primaries and secondaries a few times and actually recreated the sticking open problem with the secondaries. I figured would do no good to fix the problem and leave the crud, so I used some carburetor cleaner to clean the bores and the blades. Then loosened the secondary blades, snapped them open and shut a couple of times. The seemed much easier and to close and I could not replicate the sticking, so I tightened the blades and reassembled. Took her out for a drive and it worked perfectly. Had to reset the IAC and idle details. Took it out for a drive and seems to have solved the3 problem. Will continue to stress it for a week or so before I am confident it is fixed. At least I know how to get temporary relief.

The video starts out with some short clips of the problem.