Starting and idling problems

Boony405hp said

What is an acceptable drop off in PSI if you were to prime the pump only and then watch the gauge over a few minutes?

Car is still starting a bit rough but then after a bit of spluttering etc for 10-15 seconds it sorts itself out and idles fine.

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The factory test:
Install the fuel pressure gauge: Start the engine and allow the fuel system to reach maximum pressure. Turn the ignition off.
NOTE: Fuel specification is 407 KPa +/- 34 KPa (59 psi +/- 5 psi).

Monitor the fuel pressure gauge for a minimum of 5 minutes.

NOTE: The pressure should not fall below 241 KPa (35 psi)

If everything checks out good with your fuel system ,You may want to contact Hotwire harness and ask their Tech about your problem. The factory system requires a scan tool to perform Electronic Throttle Relearn for idle problems . Maybe it will require a modified tune to fix the problem.