My vehicle is a manual 4-speed transmission with the 2.5L inline four engine and the whole truck is completely stock. When starting from first gear, I am able to accelerate and begin moving but then it cuts out after like, 2 seconds or something really short and no power is being sent to the wheels to keep me moving, but then the power surges back and throws me back into my seat as it begins accelerating again. When I'm higher up in the rpm range, it doesn't cut out nearly as much as it does when I'm starting from a dead stop. There are no dips in power or surging while idling. It idles perfectly fine. It only happens when I am trying to accelerate. I'm sick and tired of it and I want to know what I have to do in order to fix the problem. I did some research and it might be my egr valve is crusty and gross or one of the egr lines aren't plugged in. Please help!!!

 

Welcome to the forum

The computer runs the engine in 2 modes
Open Loop is used when engine is Cold, computer uses "tables" in memory to set air:fuel mix, in this case for a 2.5l engine, computer also uses a Choke setting which runs engine Richer with higher idle until Coolant/engine warms up, but O2 sensors also have to warm up, O2 sensor can't work until its above 600degF, which is why O2 sensors are heated

Closed Loop, computer can now use the O2 sensors to get Feedback on the air:fuel mix

Does your 2000 Ranger do the same thing Cold as you describe or does it only do it warm(closed loop)?



Just to take it off the table I would do vacuum leak test, its easy
After engine is warmed up and idling, unplug the 2 wire connector on the IAC Valve
Idle should drop down to 500rpm or so, barely running, or it may even stall, either is GOOD, it means no vacuum leak
If idle doesn't drop then you have a vacuum leak, and that can cause what you describe.


EGR leak, EGR is only used once engine is warmed up fully, so if engine stumbles when cold EGR is off the table
To see if it is EGR issue unhook the vacuum hose on the EGR valve and plug the end of the hose, screw or bolt or ??
Then drive it, if stumbling is gone after warm up then EGR is the issue.


TPS, throttle position sensor, not a common failure but does fit description of problem
The TPS gives the computer a "heads up" that driver has pressed down on the gas pedal, its a variable resistor like a light dimmer or volume control, and it could get a "dead spot"
The computer sends the TPS 5 volts, computer then gets back 1 volt when throttle is closed.and up to 4.5volts when throttle is Wide Open(WOT), so as the TPS voltage goes up computer adds more fuel for acceleration, on a carb this was called the accelerator pump, thats the function of the TPS, instant acceleration
If there was a "dead spot" then computer would "think" you took your foot off the gas pedal, until you pushed down more and passed the dead spot in the TPS
This is a long shot