I have a 2000 Ranger, 4.0L v6, that knocks when going up hills, or when accelerating. It is actually a little weird, even on the flat when going around 40 mph, if I accelerate just a little it shudders and hesitates. If I let off just a little it will smooth out. If I push harder on the gas then it will pass through the shuddering and accelerate. If I accelerate hard enough then it knocks. Sometimes when I first start it, it idles a little rough but then smooths out.

I have replaced the spark plugs (they needed replacing) and the wires (they probably didn't need replacing). Ran a little better after the new plugs, but still has this issue. I am not sure where to go from here. I have had to replace a couple of vacuum hoses in the past, but can't tell if I have a vacuum leak now. Those things are stinking hard to find. I've seen things saying this could be a bad EGR valve, but I can't actually figure out where it is. I bought the truck new in California, so I assume it has one. It is just not where any YouTube videos I find show it being.

I am not getting a check engine light or any codes.

I would appreciate any suggestions anyone might have.

 

How many miles are on your 2000 4.0l?
a. The PCV valve sticks out the rear (firewall) surface of the left (driver's side) valve cover.
CAREFULLY examine the large "L" shaped plastic pipe which goes across the back of the heads (parallel to the firewall) then forward to the intake.
It cracks with time.

Just for giggles, get the tank near empty and try running premium gas.
It is said "Our 4.0 SOHC can run on regular gas-Hurray, hurray, hurray!)
It can because the ignition is retarded when the knock sensor hears knocking.
Those sensors rarely fail but the wiring to them can.

The EGR valve is plainly visible next to the throttle linkage's decorative cover.
In fact, the cover has a cutout to clear the EGR valve. They do wear out/break, but I don't know how often.
Also, the pressure differential gizmo which controls it can fail.

The vacuum lines (soft rubber hoses) are covered with ridged, black "loom".
A pair of them go from an upper reach of the intake manifold and feed the EGR valve and the Pressure Differential gizmo mentioned above.

 

I have around 170-175k miles on the truck. I've had to have a few things repaired over the years, but generally has been running great.



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Thanks for the reply.

I think my PCV arrangement is a little different from what you describe, but I did find it on the back of the valve cover. Attaching a picture. I had not noticed it hiding back there. I'll give it and the hose attaching it to the intake a close look tomorrow. It does look a bit crunchy.

I actually found my EGR valve tonight. Feel a little silly I have not seen it before. I attached a photo for this as well. In my case, it is on the driver side fender just behind the battery. You can see the brake fluid reservoir on the top right of the photo. I feel silly because I have had to replace the hose connecting it to the intake (circled in blue) already because it developed a big crack down the length. Replaced the hose but did not register what the hose was for over there.

I think my next step is to give the hoses all a good look over. There is actually a small section on the hose from the EGR valve to the intake I did not replace before, connecting the EGR to the plastic elbow. From the elbow to the intake I replaced. That small section looks pretty crunchy as well.

I have run mid-range gas in the ranger a bit lately, but not from a completely empty tank. Usually, I add a can of seafoam or some other injector cleaner and then run mid-grade but usually this is from a half tank or so. Might run it pretty dry and then run the top grade as an experiment.



PCV valve. The hose to the intake comes up and forward, but does look a bit crunchy and aged.

EGR valve. Actually, hiding on the fender behind the battery. You can see the brake fluid reservoir in the top left of the photo. The battery is just outside of the photo on the bottom right.

 

Are you sure you have a 4.0l? I think it might be a 3.0l.

The thing you circled in red in the second photo isn't the EGR valve.
It's the air intake for the EVAP system.
The green plastic cap at your circles 8 o'clock position is where you'd hook up a smoke machine.

In the upper half of the red circle in the first picture you can see the vacuum source.
It has the 90* rubber elbow and 2 ridged loom (protective covered vacuum) lines.
Follow these to your EGR valve....by way of the pressure differential gizmo.

 

Definitely a 4.0L. I think I read somewhere that they changed the 4.0L between 2000 and 2001. I think mine is the older OHV version and they switched to SOHC in 2001.

 

Ahhhh...That's why it looked different in those close-ups.