The car in question is an 88' IROC 5.7L car. Mods are: Edelbrock shorties and ORY, !cat, GMMG cat back, free mods, 180* stat. I'm using a modded AJUL BIN. When the owner removes the Moates adapter and my BIN and reinstalls his stock chip - the surge is gone, but the fuel mileage and road manners go to crap. The car has 77K original miles, 2.77 gears, all the basic tune up crap has been replaced within the past 3K miles. One thing I want the owner to change is the 02, still has a single wire 02. I feel a 3 wire sensor would get rid of some of his issues.

Any thoughts? Input? I haven't had a chance to scan or data log. Is there anything I should be looking for in particular?

TIA

 

I think I'd check and see if someone enabled hiway mode in your modified bin. if so, its either to lean or to much timing in the tables.

 

I 100% agree. The custom tune most likely has too much timing either in highway mode, or the base map has too much timing which pushes the highway mode timing above what the engine wants. Also double check the base timing value in the .bin and make sure the base timing on the engine matches that.