Car is a 2000 Impala with the ZZP SSM90 kit (4.0 pulley), Wizard Air intake, and Plog/catback. Runs pretty well overall but had a few concerns, especially after my first scan. Biggest issue I'm having is the car has a tendancy to start trailer-hitching at part throttle, particularly when going up hills. I can visibly see the rpm's hunting by 2-3 hundred while this is occuring. Doesn't do it at heavy/full throttle or when the car is warming up. I started checking for vacuum leaks but haven't found any yet. Also, replaced plugs/wires and ran a fuel system cleaner through.

Other issues after scan are ltft locking in at 3.1 and I know ideally they should be at zero. Also, during full throttle runs the timing is usually very low (11 degrees or so) but will sometimes suddenly jump to 17 degrees as the rpms increase. Then it feels like somebody hit the "NAS" button. It is a ZZP tune for their kit and I've heard then are rather conservative with timing but I don't understand the occasional sudden jump. I also sometimes get a bit of tip-in kr so maybe this has something to do with it.

I am certainly new to the tuning bit but am working on getting up to speed. Ordered a wideband as well as a couple of books on tuning to help my efforts. Certainly would appreciate any tips on these issues or feedback on the scan. Scan included both a part throttle with the hitching effect as well as a first & second gear full throttle run.