I suspect if you look in the "aircraft.cfg" file for your floating planes you will *not* find a heading that looks like this  
[contact_points]
     //0  Class
     //1  Longitudinal Position        (feet)
     //2  Lateral Position             (feet)
     //3  Vertical Position            (feet)
     //4  Impact Damage Threshold      (Feet Per Minute)
     //5  Brake Map                      (0=None, 1=Left, 2=Right)
     //6  Wheel Radius               (feet)
     //7  Steer Angle                     (degrees)
     //8  Static Compression           (feet)  (0 if rigid)
     //9  Max/Static Compression Ratio
     //10 Damping Ratio               (0=Undamped, 1=Critically Damped)
     //11 Extension Time               (seconds)
     //12 Retraction Time               (seconds)
     //13 Sound Type
     //14 Airspeed limit for retraction (KIAS)
     //15 Airspeed that gear gets damage at (KIAS)

note, this is just the heading the actual data is of course a string of 16 numbers for each point
I beleive fs2000 like cfs1 uses data from the *.air file to position the model in the sim where as cfs2 looks first for the above data in the aircraft.cfg try cutting and pasteing the data from the most similar default plane having first backed up any thing you mess with

IM NOT SURE WHAT PLANE YOU ARE WORKING WITH. IF YOU CAN COPY THE INFORMATION FROM A STOCK AIRCRAFT AGAIN THAT MIGHT HELP. I HAD A PROBLEM ONE TIME WITH THE SAME ISSUE AND ANOTHER JUMPING ALL OVER. DOUG ATTRELL HELPED ME TO FIX THE PROBLEM BY SENDING ME THIS INFORMATION. MAYBE THIS WILL HELP

It's very difficult to set the gear positions accurately as without the designer's source file you're
working from a theoretical reference point. This point is where all AIR file/Aircraft.cfg
variables are measured from. Adjusting them involves experience & guesswork. Sometimes it
won't work or even make things worse despite all your best efforts.

When you first use FS98, CFS1 or FS2000 aircraft in CFS2 new entries will be written to Aircraft.cfg. These are easier to tweak & the new CFG entries will take preference over those in the AIR file.

Open Aircraft.cfg of any default aircraft in Notepad for an explanation of what the entries do.
(Tips or comments are shown after a // or ; remarked entry.)
As this is a P-38 I'll use the default P38F_LIGHTNING as an example. For the static position on the runway you need to tweak the [contact_points] entries.
Here's how I do it. Start CFS2 & select your P-38 in Free Flight. Hit the Y key while it's loading & when it loads go to Spot View. This will put you in Slew mode & show you the static_cg_height & static_pitch positions in Aircraft.cfg. Here's the height & pitch entries from the default P-38F.

static_cg_height=6.27        //(feet) altitude of CG when at rest (altitude when loaded on ground)
static_pitch=6.39        //degrees (pitch when loaded on ground)

Now hit the Y key again & note the difference. This will show you the actual gear positions defined
in the first 3 [contact_points] entries. You can toggle between the 2 positions with the Y key.

I start by adjusting the static_cg_height & static_pitch first. This is mainly guesswork & can be
time-consuming & frustrating. static_cg_height is the height in feet between the ground & that
theoretical reference point. static_pitch is the angle in degrees of the attitude of the aircraft on the runway.

Once it looks right in the Slew (Y key) position you can start adjusting the actual gear positions.
This can usually be fixed by tweaking the gear vertical positions that I've shown in Bold type in
this example. Negative values are below the reference point. point.0 is usually the nose or tail
wheel.

point.0=1,   6.96,  0.00, -7.45, 1600, 0, 0.93, 37.7, 0.40, 2.5, 0.95, 2.5, 3.0, 0, 0, 152
point.1=1,  -3.20, -8.12, -6.55, 2200, 1, 1.40,  0.0, 0.55, 2.5, 0.75, 5.5, 5.0, 2, 0, 152
point.2=1,  -3.20,  8.12, -6.55, 2200, 2, 1.40,  0.0, 0.55, 2.5, 0.75, 6.5, 5.0, 3, 0, 152

You will need to exit CFS2 & start it again after any tweaking. Please make a backup copy of any files before modifying them.

The idea is to make the model sit exactly the same from both sets of entries, with & without pressing the Y key. Once that's done the aircraft will usually be OK. You might need to tweak a stray Scrape point to fix it properly.