Fuel Issue? What?

[AnnoyedEasy3]

1990 Bronco 2 2.9L V6
OK, Here is the symptoms my truck starts right up and idle's at 1200 RPM and idle's just fine with no fluctuation. While it is still in Park I press the gas pedal and it rev's just fine I am able to hit 4k+ RPM.
It is the same way in neutral runs good sounds strong.

BUT when I put it in either Reverse or Drive/OverDrive, I press the gas and it acts like it wants to stall out. But it doesn't stall out, it just stops accelerating just rumbles really low. Then soon as I let go of the gas it goes back to idling fine. I can drive the truck around the neighborhood while just barely giving it gas not to exceed 2k RPM and 25 MPH it seems.

I was told to try replace/repair a few things so I did.

Fuel Pump
Fuel Filter
Fuel Pressure Regulator
Ignition Coil
Throttle Air Bypass Valve
O2 Sensor
Catalytic Converter
Muffler
Distributor Cap
Cap Ignition Rotor

 

[rookieshooter]

Torque converter? And welcome to the site.

 

[janderson4010]

throwing parts at something is never a good idea, you need to diagnose the problem, and then replace the parts that are actually causing the problem. I have gone through and made educated guesses that have led me to replace pretty much all the parts you just mentioned to fix a problem i've been having that followed me from my 2.9 through to my 4.0 that I swapped in. Your money would be well spent in setting your timing, and checking fuel pressure, both of which need a reasonably inexpensive tool. It does seem to me that your transmission is playing a part in your difficulties, is there anything else at all that your transmission does, slip etc? When did this problem start? how does the fluid look?