On a S code, can you install a boost fooler type resistor on the vac map sensor? that should fool the cpu into thinking that it has vac?

Hi
You can made this little circuit, and connect on MAP and both vacuum solenoid.
Or you can re flash the ECM.

what is involved with a reflash? is it just a quick dealer update that can be done for cheap?

Wow thats a diagram! Think thats over my head. I put a boost fooler (10k pot) on my map sensor to get rid of the codes & defueling problems with high boost . I was thinking that I could do this on the vacuum side . It"s simple . Has anyone tried this?

You still have SES light and fault cod for EGR system.
One way is to install a EProm from a F-engine into the CPU.