Quote:
Have mechanical boost gauge. it gets up to 30psi at times
That is TOO high, going above ~27psig can certainly cause overboost condition and put vehicle in limp mode.
Ask me how I know this! HA HA
The MAP sensor runs out of range around 27psig +
Some possibilities,
Bad MAP sensor?
Tune is pushing boost pressure to far during peak load events?
Turbo vanes actuator rod is misadjusted or vanes is sticking and not backing off quick enough.
Again, first thing I would do is change the MAP sensor. If it is giving a low (incorrect) boost signal to the ECM, the ECM will continue to try and push the boost when it sees a low pressure signal from the MAP.
Use the Bosch GM 55206797 New GM PN: 55568175 MAP sensor, it is much cheaper than the Mopar sensor.

the part number, plenty of them available online.
Adjust the turbo vanes actuator rod to get a little less boost at full stroke? (Only AFTER ruling out MAP sensor)

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
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