Im having these issues on the van and its driving me nuts. When I start it up cold I get a lot of random cutouts that make the tach drop. Once it warms up it acts fine but still has spells of cutouts every once and a while, especially after slowing down and speeding back up. The other issue I have is if I go over about 4000-4500 rpm at WOT I start to lose power and it starts misfiring once I let off the gas it continues to misfire until I come back to an idle and wait for it to clear up. Afterwards I get a lot of cutouts like when it's warming up.
Ive done some testing at idle when I am getting random cutouts, when watching coil signal it drops out every time it cuts out. I have had 2 different HEP's in it and they both were pretty much equal. Ive watched REF voltage going to the HEP and that stays constant. Ive also tried wiggle tests of every connector and wire from the HEP to the SMEC with no changes. I have no bare wires anywhere and Ive re done the grounds at the intake, neg terminal to body, and SMEC to body.
This didn't start until I put in my +40's and 3 bar in and I socketed the SMEC that was in there at the time. I originally thought it was the Ostrich so I ditched that and put a burnt chip in and nothing changed. I recently though I was a socket problem so I put in a flashable SMEC from Rob and it still does it. The PM board is different too.
I have yet to try a scaled stock cal but its on my list, I also plan to borrow a lab scope from work and watch the HEP signals and see what they do.