So I just changed out my injectors because of hard starting after the car was hot or driven. After the injector change the car now starts hard and stumbles off idle when cold but starts fine when hot. I have a 88 5.7 TPI. Fuel pump was changed last year. I changed the fuel regulator diaphragm along with the injectors. I used 22# Delphi injectors. I also checked for vacuum leaks. Any ideas?

 

I'd look into the cold start injector for proper operation. And check that the fuel pump is running for a few seconds when the key is first turned on.