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Please Help me! 2002 explorer bucking

024x4beast

Member
Joined
September 13, 2012
Messages
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City, State
Lakeside,CA
Year, Model & Trim Level
2002 Ford Explorer XLT
Im new to this forum in a desperate attempt to find help for my explorer.

Its a 2002 XLT 4X4 4.0 V6.

Everytime i am accelerating uphill my car feels like its bucking, slipping, missing, misfiring...SOMETHING! We have so far ruled out the first thought of transmission and the spark plugs and wires. car does not pull any codes or flip any dash lights.. it almost feels as if its in the drivetrain, maybe its catching? there are so many possibilities. any input?
 



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May be way off, but when was the last time you changed the fuel filter?
 






Start by checking your differential fluid LEVELS. Make sure they are full...

You have ruled out the transmission huh? Ok then next...

How do you know it is not the plugs/wires? Pull them ALL.
Be mindful of this: Only use MOTORCRAFT Plugs and Wires and gap them to specs... I think it is around .54 exc...

If you have pulled your plugs and checked the gap exc.. Next...

Check your Air Filter, throw a new one in there.
Clean your Mass Air Flow Sensor (Next to the air filter housing) http://www.explorerforum.com/forums/showthread.php?t=350613
Clean your IAC Valve (Next to the throttle body)
http://www.explorerforum.com/forums/showthread.php?t=84220
Make sure your brake booster line and all other vacuum lines have absolutely no leaks.
 






Run as much gas out of your tank as you can.

Put back in good 87 octane gas

Change the fuel filter (pita by the way) http://www.explorerforum.com/forums/showthread.php?t=198626

Take a can of sea-foam (8 bucks at walmart) white can - pour half in breakbooster line, shut the truck down (if it hasn't died yet) pour the rest in the gas tank
Run it down the road.

+
 






Check your brakes too. make sure they are not locking up.
 






Run as much gas out of your tank as you can.

Put back in good 87 octane gas

Change the fuel filter (pita by the way) http://www.explorerforum.com/forums/showthread.php?t=198626

Take a can of sea-foam (8 bucks at walmart) white can - pour half in breakbooster line, shut the truck down (if it hasn't died yet) pour the rest in the gas tank
Run it down the road.

+

Half in the brake booster? Never heard of that, tell me more..
 






wow thanks all for your much needed help. fuel filter is the next order of business. and then the other things. i will keep yall posted on how this comes out
 






Half in the brake booster? Never heard of that, tell me more..

I found it to be the easiest way to introduce cleaning solution directly into the engine. Or you could just dump it all in the gas.....
 






wow thanks all for your much needed help. fuel filter is the next order of business. and then the other things. i will keep yall posted on how this comes out


I wouldn't prioritize the fuel filter above checking simple things like the air filter, oil level, gear oil levels, cleaning maf exc

Just a thought, that fuel filter is going to kick your butt...



Also, you are very welcome and I hope your truck runs better

Good luck!
 






well went through and checked the throttle body and the MAF. throttle body was pretty dirty but the MAF is brand new. i forgot to mention i bought this car a few months back so im still getting to know it and trying to figure out what has and hasnt been done to it yet. Tried to get to the fuel injectors to find that we cant because one of the bolts is stripped and we cant get it out (even took a hammer and screwdriver to it to no avail). Also the spark plugs and wires were gapped correctly to exact. and wires are not faulty.

today is going to be going through all vacuume hoses and the 4x4 module to see if that is the issue... anyone know where thats located behind the glove box? like more of a specific location.

we will also be going through the IAC valve today and then test driving to auto zone for dif fluid and the special tool the fuel filter requires -.- annnnd finally some sea foam..

if none of this works im gonna be stumped!
 






Well...I feel like an idiot! I over looked my real problem for a month! I have the same vehicle. I changed out the DPFE sensor. It DID make a difference. But, only a small difference. I changed out the fuel filter. It, too, made a difference. But, only a small difference. The vehicle DID run better. BUT, it was not the source of the REAL problem! It still performed as you described...though, not as badly. So, I'm guessing that both were bad. I thought I had fixed it!! BUT, after the vehicle began performing better, from the two other parts being replaced, it then began to get worse...AGAIN! And, in only a few hundred miles.

The fuel filter had not been changed in 80K miles! The DPFE, had never been changed out (130K miles). Now...I found ONE thing. My plugs, and wires were a year old. I thought..."They couldn't be bad!" However, I had one plug that looked much worse than the others. One coil, in my coil pack was going bad! So, the plug in the#1 cylinder had a burned down positive electrode. The gap had gone from .054 to closer to .080, and had tan soot caked all over the end. It was the COIL PACK! Not the whole thing, but one coil that was bad. Though, I think the whole thing would have gone, a short while later. I changed it out today. It now runs as good as new!

I can't say that is your problem. But, your description of your problem sounds just like mine did.
 






well... i am STUMPED!!

ABSOLUTELY STUMPED.

I have gone through just about everything I feel I can on this car and yet nothing is helping!

It still bucks going uphill between 1500 and 3000 RPM's, seems to get worse when its warm outside, its gradually getting to the point where it does it anytime, uphill, downhill, flat ground, my MPG's are way down (180 miles on a 22.5 gal tank) and now i have a deep purr coming out of my exhaust.... :mad:

I have cleaned out the MAF censor, the IAC valve, changed over all fluids, seafoamed the daylights out of it (i dont think its ever been done before on this vehicle), we even plugged the OBD 2 reader into it eventhough this problem isnt setting off any dash lights (it didnt pull any codes however my O2 censors look a little finicky so i ordered some new ones of those and are waiting on them to come in), we have changed the spark plugs and wires and checked them 10x over, we have changed the fuel filter and checked numerous times for vacuum leaks.

does anyone have any other ideas of what this might be?

we thought maybe the flywheel is ground out and not allowing to get into the next gear properly?

or maybe the 4x4 module (control shift module)?

I feel like i am the only person who cannot figure out what this problem is, I am on a budget so taking it to the dealership or shop is just out of the question at this point.

any thoughts and help would be VERY MUCH appreciated!
 






Symptoms I had when I upgraded my throttle body and damaged the TPS spring.
It did however, throw a CEL and a po122 code. Be careful if removing the TPS,
Loctited self tapping Phillips screws into soft plastic is a recipe for trouble. GL

http://www.explorerforum.com/forums/showthread.php?p=2349296
 






Once again, I had VERY similar troubles. Mine ALSO got worse in warmer weather! I feel it HAS to be something in the ignition/fuel system. I had a bad coil pack. This led to one of the plugs going bad. You might have a problem with a crank trigger. Your O2 sensors, COULD be bad. Or, a few other things. BUT, your symptoms were the SAME as mine. In my case, it was my coil pack. I think it has to be in your ignition system. Of course, it COULD be the computer. This part CONTROLS the ignition/fuel/everything!

This seems to be a lean misfire condition. That can be either ignition, or fuel mix. The fuel part can be tricky. It can be a vaccuum leak. An EGR system malfunction, a sensor, etc. But, among the obvius suspects is the DPFE. It is prone to going bad. It can cause a faulty reading to the ECM, and make the car think it's running fine, when in fact, it could be lean. I replaced mine, and it runs better. Though, again, my main problem was the coil.
 






If you think it is related to the 4x4, do the brown wire mod to disengage the 4x4.

If you don't want to do that, remove the front driveshaft and drive it.

Post results
Good luck.
 






well theres a new symptom now, only in drive when at an idle the rpms go from normal (between 7-8.5) to less than 4. you can feel that it wants to stall but just when its about to the rmps spike. this happens the duration of idle time. still havent removed the 4x4cm or driveshaft...its been hot as h*** outside lately! hoping to get to it tomorrow but in the mean time wtf is this new thing happening?
 






Try a new motorcraft or screamin demon coil pack. If it doesn't help, send it back.
Don't forget to disconnect your batt and hold your brake petal or something for a while whenever you do anything.

O2 sensors, replace them too I guess... don't forget to disconnect batt.

Have you "listened" for a vacuum leak?
Have you gotten rid of all of the previous gas?
Have you done the BWM or removed the front drive shaft?

If all this fails, I lean twords transmission. I'm very sorry.

Good luck,
Post results! :)
 






Now would be the time for that fuel filter also -Hint Hint.
 






Apanello-- thanks for all of your advice on this topic i cant tell you how much help you have been.

Just to recap

Have done:
cleaned MAF censor
Cleaned the throttle body
changed the O2 censors (all 4)
cleaned out the air filter, its a k&n
ran seafoam through the breakbooster vac line and through the gas tank
changed a belt pulley
new spark plugs and wires (checked 1000x over)
checked for any vac leaks or shot fuses or ground issues
emptied gas tank and refilled with good 87 octane
disconnected the battery to reset all.

still to do:
pull front driveshaft
get new 4x4CM
get a new coil pack


I just know that this isnt a tranny problem due to the fact that the car still shifts into gear perfect.

the bucking problem only happens::::
1. warm outside/warm engine
2.uphill accelerating
3.between 2nd and 3rd gear
4.between 2000 and 3500 RMPS

the idle issue only happens:
1.warm outside/warm engine
2.going downhill
3.in drive but at an idle
 



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Hey by the way, I strongly recommend you hit up a transmission shop for a free diagnosis and their opinion before spending any more money. It could very well be your clutch bands slipping under load.....
 






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