82 vette engine surging

Hey gang! I have a simular problem on my 82. I have no idle problem but eng has a minor surge, usually just before upshift. Seems more noticable after driven 30+ miles and high ambient temp. I have done all the regular maint stuff using delco parts. I have scan checked and there are no codes or readings out of spec. The 02 sensor is a bit slow to warm up and readings a bit sluggish. As I recall this was very common on early GM EFI and was mostly caused by very slow ECM baud rate rather than actual sensor problems. Either way I am replacing the 02 as preventative maint.

I have not checked the fuel pressure yet but suspect it may be just slightly on the low side which would cause these symptoms. The fuel guage is not very acurate either so I was already planning on replacing the tank sender, so I will probably replace the pump as well.

Someone mentioned using a 85 pump. My guess is this would probably not work. 85 MPI used a working pressure of around 30-35 psi. Crossfire uses lower pressure 10-15 psi. Let me know if anyone has tried this and what the results were.

Thanks!
Brian