I just picked up an ‘03 4.0 5spd with 243k on it. It bucks pretty hard (the engine+trans I think) when you abruptly floor it, drop the clutch, etc. I’m thinking start with motor/trans mounts and see how that goes, any other suggestions on what the replace?

 

Clean the MAF sensor, easy to do
Dirty MAF sensor is a common cause for stumbling on the 4.0l engines of any year

To test motor mounts
Set Parking brake or hold foot on brake pedal for the test
Open the hood so you can see the engine from the cab under the gap
Start engine
Put trans in 1st and slowly let up clutch pedal, engine should start to raise up on one side, quickly push down clutch pedal, should be NO "clunk" sound
Now do the same but in Reverse, engine will raise up on the other side

No clunks or no high lift of the engine on one side means motor mounts are OK


A good tool to have is a Bluetooth OBD2 reader
These work with any smartphone as the display, and cost under $20 usually, APPS are free
You can, of course, get and clear Codes, but main reason is you can see "Live Data", so you can see what Computer "sees" from each sensor
These work on ANY VEHICLE sold in the US/Canada from 1996 and up, it was/is the Law, so not a Ranger thing or even a Ford thing, ANY VEHICLE

With that tool you could see if Throttle sensor(TPS) is working like it should, TPS gives the computer a "heads up" that the driver wants to accelerate and by how much, these rarely fail but rarely is not never
Its usually a mechanical issue like dirty MAF sensor or an air leak

 

Will do! New trans mount is on the way but I haven’t sprung for new motor mounts yet, thank you for the test procedure!