[olopezm]

Using a vacuum gauge:

Connect the gauge to a suitable vacuum port BEHIND the throttle body. Watch the needle and take note of the reading, now raise the rpms to 2500 and look at the gauge, it should be slightly higher than at idle. If it starts moving down to 0 there's a restriction in the exhaust.

Using OBD data:

Check the reading of the map sensor with key on/engine off (anything between 24 and 29.9 inHg depending on your elevation), start the engine and compare the reading, it should be a lot lower than before (around 9 inHg). Now raise the rpms to 2500 and watch the reading, it should be lower than at idle; if it starts going up to the reading at KOEO the exhaust is blocked.

Oscar.