Hi all, posting this in case anyone else has a similar issue. I’m running speed density with ECMLInk using an OmniPower universal 4 Bar MAP sensor.

It’s been fine for 5+ years but recently developed what started as a very infrequent and an intermittent issue of the car misfiring and then at times under boost a major stumble, bucking. It got progressively worse and reached the point of almost every drive. I checked and tried all the usual suspects to no avail:

Checked for boost leaks - pressurized it to 35psi and held pretty good for 15+ seconds
Plugs
Spark plug cables
Coil pack
Igniter (a/k/a transistor)
Checked ECU (opened it up, no leaking capacitors, looks pristine)
Checked all ECM link connectors
TPS
Checked TPS pigtail
Checked fuel injectors - all clean
Replaced CAM position sensor
Put in new Deatschwerks Fuel pump
Checked wiring on fuel pump re-wire, all wires and terminals were pristine
Battery cables and grounds solid

At the end the problem was my OmniPower 4Bar universal MAP sensor was failing / had Failed. I changed it out with a new one and the idling, stumbling issue, which by now was almost constant was instantly solved 100%.

Hopes this might help others with SD and this Omni Power 4 Bar sensor running speed density.