I think you mean 1600cc or 160lb and no the pressure is not too high. Lots of people run 60 to even 90psi base. Most of the GM cars now come with 58psi from the factory. Some of the 160lb Bosch injectors are a bit non-linear at part throttle and can take quite bit of tweaking to get dialed in cleanly. It sounds like you have too much pulse width and need to get a couple clean points and interpolate between them if possible to fill the table then tweak from there. What injectors and EFI are you running?? Some others may jump in with a bit more info.
I'm using 1680cc (160 lb) bosch white tops with e85. Base fuel pressure is 43. Its a bit tricky to get them to idle and drive clean but it can be done.
Here's some things that helped me.
Make sure to hook up vacuum to the regulator. Itll bring the fuel pressure down at idle and cruise
Set up a minimum pulse width. Mine would cut out and surge at anything lower than 1.5ms.
Turn closed loop off at low rpms. CL kicks back in on mine at 1800rpm
Set a commanded cold idle rpm for around 1200, this will help keep the engine running and not stall out when cold
Keep working at it, it will take time to get the tune clean and steady at all different scenarios. Cold/hot/in gear, ect.
Once you get it to run ok and it can move under its own power, grab a buddy and have him drive while you tune. Try and get into every possibility imaginable. Get the base table real close so closed loop doesn't have to deviate to far from base. (I like to see no more than 6% + or -)
Keep working at it. And dont discouraged, i wanted to give up on mine, was getting pretty fed up, but just kept working the tune and making improvments.. I have mine where a can reach in and fire it with no issues and jump in and go drive around when stone cold. Warm Idle at 800rpm smoothly. 14:1 afr @idle [email protected] cruise.