Stumped. Having a problem. About to take a road trip.

[FloridaGrown]

If anyone could throw some ideas around that'd be greatly appreciated. I've got a 2000 Ford ranger xlt sport 2wd 4.0l v6. My truck runs fine it idles smooth, cranks generally quickly and overall is in good running condition. Once in a while though it will just suddenly jerk. Like a random misfire or the torque converter is locking up. I don't think it's the transmission but I'm no expert by any means. It dosent matter the speed, the environmental temperature or any specific time. Hints random. There's too many variables for me to look at one specific thing to troubleshoot. I've replaced the coil pack, spark plugs, wires, oil and filter and the fuel filter. I'm about to take a road trip from Gainsville, Fl to west palm beach, FL. It's a total of 314 miles doorstep to doorstep. I'm a bit worried. The truck has never failed. I just don't want to be stranded. Funds are tight and I'm moving to start my old job back working on caterpillar marine diesel engines and this isn't an opportunity I want to postpone. Any help would be greatly appreciated. Thanks in advance. Aaron.

 

[RonD]

Clean the MAF sensor, common issue on the Rangers, especially 4.0l's
Good read here: http://www.therangerstation.com/tech_library/CleanMAF.shtml

And it's cheap

And keep track of your foot position on the gas pedal, as far as the bucking goes.
The computer reads where the gas pedal is with the TPS(throttle position sensor), inside of it is like a Volume control or Light dimmer, it is a variable resistor.
It is on the upper intake attached to the throttle shaft opposite the cable hook up.
Computer sends it 5 volts
TPS sends back .9volts if throttle is closed, then as gas pedal is pushed down voltage increases, above 4.6volts is Wide Open Throttle

If you are getting a warn spot on this variable resistor then voltage may suddenly drop, then come back, so engine would buck.
You can test these with an OHM meter, or volt meter.
TPS is a long shot but not a 0 shot