Thermoquad tuning on 318

sounds like the accelerator pump is AWOL and or the fuel level is too low, and/or the low speed circuit has a problem. Check for a missing checkball in the pump circuit.
if it was me I would disable the Secondaries first then retest, and leave them wired shut until you resolve this tip-in issue.
BTW on a 318/TQ, if the secondaries open in neutral, the Airdoor is most likely set too loose.