06 MPV driveability issues

I am a missionary in Guatemala who was donated a 04 MPV with the Ford Duratec 3.0. I have access to the Autel Maxisys Elite scanner. The van throttle surges under load in the hills and sometimes has no power at all. When it drive and sitting in traffic the idle is very high and you have to keep your foot firmly on the brake. If you put it in neutral it revs up to almost 2,000 rpms and the engine feels unbalanced. I have scanned it and found the stfts are running -14. I have searched endlessly and found no vacuum leaks. There is a evap leak detection pump that is reading 37, the highest number it can read. I'm not super familiar with driveability issues or scan tools as I am more of a suspension expert. Any help would be appreciated. I have a team coming in May to take on a mission trip which is why the van was donated and I can't use it in it's current state.

Welcome to the forums! I figure you'd have mentioned it, but any trouble codes found? Your title says the MPV is an '06, but your post says '04? Not trying to nitpick, but it may matter when finding service info and wiring diagrams.

It sounds like there may be multiple issues at work? I say we start with the idle issue first, as this sounds like somewhat of a safety concern. Could you observe some scan data when the engine idles high? Engine speed, IAC%, TPS voltage, ECT, throttle position mode (C/T, P/T, WOT, sometimes shown as ThrPosMODE) are the PIDs to watch. This'll tell us if the PCM recognizes the high idle and is working to control it, or if there's some kind of input problem.

While you're gathering data, maybe hop over to Global OBD and have a look at Mode $06 data. TID $53 should be the ID for misfire counters on this Mazda. See if any specific cylinder has higher counts than others. That might give us direction on the 'unbalanced' feeling and surging issues.

Having a negative fuel trim means the PCM is seeing a rich condition so it is removing fuel.

Sorry I did make a mistake with the year, it's definitely a 04. This car has yet to throw a code even though it's runs terribly. There are no historic codes either. It runs great until it warms up. I will rescan it and provide you the data your asking. I will tell you this much under the live data portion of the scanner the misfire counter always says zero. I have also told it to individually shut a coil down on each cylinder
one by one through test modes and there seems to be no issue with getting spark because they all respond the same way.

Was the fuel trim "-14" or +14? Sometimes "-" is used to refer to a number and definitely confusing when in front of a fuel trim number.
We had an MPV a while ago that acted like it had an air leak - we couldn't find it until our new smoke tester arrived and we saw smoke pouring out between cylinders 3 and 4 - the hardest place to look on an MPV if it is a sideways mounted engine.

Here the info I pulled today after the van was warm and running badly.
Throttle pos. V 1.03
Tps % 20.78
Relative TP .39%
Stft 1 -0.78%
Stft B1S1 -0.78%
Stft B2S1 0.78%
Stft B2S2 99.21%
Stft 2 0.78%
Spark Advance 6.5
Ltft 1 -10.93%
Ltft 2 - 7.03%
Mass airflow 1 0.01 lbs
Mass airflow 2 0.72 v
Idle air control 25.37%
IAT 107.6 F
IAT 1.4 v
Engine RPM 714.25
ECT 192.2 F
ECT 0.62 V
Ambient air temp 91.4 F