hey guys i just signed up here looking for some help. i have a 2000 ranger 4.0 4x4. i just started having this problem, cruising along at 60 Km/h (35 mph) under light acceleration, or cruising up a hill it kinda bucks and and hesitates a little bit. it kinda felt like a miss but i checked all the wires and i just changed the plugs 3000 km's (1800 miles) ago with motocraft plugs, i checked the TPS voltage and its rock steady all the way from closed throttle(.95 volts) all the way to WOT (~4.50 volts), i cleaned my mass air sensor and that helped with another problem i had with throttle response but the hesitation is still there . i had a problem like this on my mustang and it was the TPS, when it comes to newer cars i feel like i am lost. any ideas? btw there is no check engine light or any thing else


also i had another minor problem since i bought the truck, from a dead stop under light acceleration its will kinda bump like once or twice but only occasionally, some one said this may be the slip yoke? i don't think its related to my other problem cause this feels more mechanical and the other one feels more like a bad sensor


sorry for the long post lol

 

Two common causes of part-throttle bucking or surging are a lean A/F mix or too much EGR.

The lean A/F can be caused by a vacuum leak, dirty injectors, dirty MAF or lazy oxygen sensors. I doubt that it is an actual fuel pressure or delivery problem since you haven't mentioned any problems at WOT.

A more likely scenario is excessive EGR. Trucks from your era have a lot of trouble with the DPFE sensor either unerreporting or overreporting EGR flow to the PCM. Underreporting forces the PCM to command more EGR than the combustion process can tolerate.

The bump on initial accel is very likely due to the slip yoke binding. Do a search on slip yoke or slip bump for lots of discussion.

https://www.ranger-forums.com/forum2...90&postcount=7

 

hmmm i have a wide band O2 meter (LM1) for my mustang. maybe i will weld a bung on the ranger and just see if it is lean (sounds like it is) plus i wanna try out some new software lol.

for the DPFE sensor, what does it look like and where is it? is there a way to test it (like a TPS) or do i just assume its bad and replace it

i guess i will grease up the slip yoke and see if it helps. even if i gotta do it every couple months i think its worth it.

 

ok i think i am retarded, i have spent 20 mins looking for this damn sensor on my truck. i looked at diagrams and pictures of the sonsor on here and i still can't fin dit. its on the drivers side i have gathered, is it attached to the EGR? there is nothing on the drivers side that has 2 vacume lines going to it on my truck

2000 ranger 4.0 (valve cover says OHV)

 

Here's an interesting dilemma: The electrical schematic says that your 2000 4.0L doesn't have a DPFE (or an EGR system) but the component layout diagram in the same book shows its location. Which should you believe??

 

my 2000 OHV has the plug in the header for the EGR but no sensor there.

 

hmmmmmm so what could be my problem then? it seemed like it was worse when i drove to work this morning, the temp outside was around 8C (46F) i also noticed it for the first time at WOT but only once

 

Do you have a stick or a auto

 

auto. and obviously in 2wd as well

 

Your original description was part throttle bucking. If it is also happening at WOT, then it should have nothing to do with EGR or feedback A/F control (oxygen sensors).

 

hey bob could it be the valve body in the trans. mine was doing something similar when the trans went out.

 

it only did it once at wot (i said WOT but it was more like 3/4 throttle cause the motor was still warming up and it was cold so i didn't wanna push it that hard, sorry for the confusion on that, my fault) and i don't think it was related to the part throttle. for some reason it hasn't done it at all today and i drove around alot today, which leads me to believe it is a sensor problem. i would think if a valve body was taking a dump i would notice it one the shifts but it shifts super smooth and the fluid is really clean (not burnt smelling or anything)

i am gonna go ahead and hook up the wideband O2 sensor and drive around tommorow and see what my A/F looks like.

 

Ok, so the problem is definetly worse when the motor is cold. i am gonna check the regular things again a little closer, plugs, wires, IAC (ya never know), give the MAF a clean again, check all the hoses. is there anything else i should look at on these trucks? i just gotta find my spare bung for the wideband and hopefully i can check that

 

When's the last time the fuel filter was replaced? A fuel pressure check would be helpful.

Also, has your truck been drinking any coolant lately?

 

coolant level hasn't changed since i last filled it in the fall really. never did the fuel filter though, i'll hook up the fuel pressure guage to it and see what it does. whats the stock setting for fuel PSI? 40 psi?

 

bit of an update. changed the spark plug wires and fuel filter. pulled some plugs and it seems normal. it is defiently worse when its cold and when it gets up to operating temp the problem goes away completely. my buddy is a ford tech so i took the truck down there and he hooked up the laptop with what ever program they use to pull codes are run the diagnostics from the port under the dash, there are no stored codes, we took it for a drive with the laptop hooked up and its shows that the truck is perfect lol. i cleaned the MAF, check vacume lines, learned i have no EGR, cleaned the air filter, cleaned the PCV, cleaned the IAC motor, checked the TPS voltage.

i am out of ideas. does this sound like a bad O2 sensor? i think if it were an O2 sensor it would be doing it all the time