PFD freezes - TOC on short route

Hello all,

I'm new to this wonderful world of the PMDG 737.

I'm using the (the now) old 737-800 with FSUIPC 5.

The problem I'm having is that in a short route (SBSP - SBCT) when at the cruise altitude the PFD suddenly freezes, with speed and altitude not updating on the PFD.

The MCP commnads become unresponsive. But the sim continues the flight and the NAV display updates.

It stays this ways for some minutes, after that, everything goes crazy: the AP disengages, the airplanes is way out of route, I find myself at an altitude way below the one before... 

After this "UFO Lost Time" event, the PFD updates normally and I can command the MCP.

I believe the problem is related to the route I've chosen, which connects a SID at SBSP to a STAR at SBCT by the exactly same point. 

The SID, PORB2A, connects to the STAR, ORAN1A, at the same point, SOVSI, with no airway between the two.

In real life, airlines use FL 260 in the following route: SOVSI UL310 ORANA. 

I can program that route in the FMC, no problem. However, when in flight, looking at the LEGS page, the point near the TOC has an altitude which is lower to the chosen cruise altitude.

The sim flies normally up until 23,000 feet. But when it gets to 24,000 feet, the PFD freezes. I've tried switching the CRZ altitude to 23,000 feet, but when it gets to 22,000 feet, the problem occurs again and again.

I have searched the forums for similar problems and what I found is this:

-FSUIPC Auto Save feature enabled: it is disabled now, but the problem persists;

- Controls: no control calibrated in FSUIPC;

- Panel State: well, maybe it is the problem, I don't know. I use a saved state with ground connections on (Chokes, Air Conditioning, Ground Power);

- Doors: Front and aft doors open, Cargo fwd and aft open (I don't know if it could be related);

Software Updates: P3d to the last one, FSUIPC 5.153, using PMDG operations Center v2. 

That's it. Maybe I shouldn't be setting a Cruise Altitude since it is a flight in an almost balistice route.

May be the problem is the noob me on this thing.

So, I'm open to ideas. If anyone had something similar and can help, I would aprreciate it.

Thanks.