Thanks. I checked that but my wiring is ok.
Maybe have to swap the fuel pressure regulator to see if that solves it.
I have this fuel pressure regulator from a '92 Sierra 2.0i DOHC. It looks a little bit different than the cossie one, but it should fit. Can I use this one to see if it solves the problem?
yes only difference is the vac pipe comes out the top. Just keep and eye on fuelling if you have a afr gauge.