2003 Explorer 4.6L Kicking or Bucking on Hard Acceleration

[red03explorer]

Okay, a little background on my driving... I am an aggressive driver with a heavy foot, always complete maintenance on time and fix issues when they come up. If I could I'd go back to a sports car, but with a family in tow... I'm happy driving my V8 Explorer.

My Vehicle:
2003 Ford Explorer NBX
Auto Trans (5R55W)
4WD (Auto)
4.6L V8
141,000 Miles

With that out of the way...

I frequently put the pedal to the metal on my explorer. Occasionally (70% of the time) the explorer starts bucking or misfiring on heavy acceleration.

I've had it checked numerous times by several different mechanics and different shops... I instruct them to drive it heavy footed to duplicate... however, only one mechanic claims to have experienced it and he was at a loss. I believe the others failed to accelerate the way I do.

My initial thoughts were...
Front Differential? Almost seemed as if it could be the 4WD trying to engage, like it detected a slip in the rear wheels.

Misfire? Idles fine, other than an odd 1500 - 1600 rpm vibration that's been a nuisance since I purchased it (117,000 Miles). Can rev it up when parked and never exhibits characteristics of a misfire.

Transmission Solenoid? I've got an occasional stumble and the occasional odd feeling shift. Also, slow to engage reverse on first start on cold mornings (less than 35 degrees outside temp). Will reverse slowly and feel slightly shaky when applying gas, but within 10 seconds the issue goes away and engages quickly if alternating from park to reverse.

Slip Yoke? I stumbled upon this common issue in the forums, but mine is a repeated kick/clunk/buck (however you wanna describe it) upon heavy acceleration. Not a single clunk when downshifting or coming to a stop.

Catalytic Converter? Possibly a backpressure issue?


Not sure how I should go about diagnosing this problem. What do you guys think? Any way that I can eliminate what it's not? I'm sure I'm not the only one with this configuration that's experienced this issue.

Winter is coming and I'd love to get this issue resolved, especially before I start adding some performance mods to it.

 

[Number4]

Read up on the BWM in the sticky section (edit- in the modified section.) There they talk about removing the fuse that controls the 4wd. Don't recall if there were any complications removing the fuse and driving. This will stop the 4x from engaging if it's the issue.
I'd say no to the cat.

 

[ExcursionMJ]

Usually when I see vehicles that buck like that it's either a coil, idle air control, or mass air flow sensor. But with the IAC and MAF you usually notice it acts up when sitting at a light at idle. I've definitely seen coils cause the issue of bucking though. My brother in law had a few coil bad and any time you would get in the gas at all it would buck. Once we replaced the coils, the car was perfectly fine. I'm not saying that is your issue, but I've driven a car that experienced exactly what you're saying and it was coils.

I also have seen numerous people come into work and get their car checked for codes. Usually when they say it's kicking or bucking it ends up being a coil or coil related issue or a MAF. Again though, you'd probably notice a MAF when at idle or at a light.

 

[red03explorer]

Number4, thanks for the tip about the BWM. I was actually browsing that thread anyway because I'm annoyed with the auto 4x4. I live in the country with a lot of gravel roads and 3/4 mile gravel driveway on my own property. I tend to speed out of my property and constantly feel the 4x4 kicking in.

ExcursionMJ, thanks for the reply. After doing some research I considered the same possibility of the MAF, but figured I'd get other symptoms like a lean/rich run and idle issues. The coils are my next step, as I replaced the plugs when I bought it but took the previous owners word on a recent coil/plug tune up so didn't replace them. I should've done it anyway when I realized the plugs looked original to the vehicle at 117k.

I'll get the coils replaced and do a fresh tune up and post back my update. Hopefully that solves the issue. I'm looking into doing a turbo install in the near future, but don't want to soak the money into it if there are any other costly repairs necessary.

 

[rogerrunnalls]

Number4, thanks for the tip about the BWM. I was actually browsing that thread anyway because I'm annoyed with the auto 4x4. I live in the country with a lot of gravel roads and 3/4 mile gravel driveway on my own property. I tend to speed out of my property and constantly feel the 4x4 kicking in.

ExcursionMJ, thanks for the reply. After doing some research I considered the same possibility of the MAF, but figured I'd get other symptoms like a lean/rich run and idle issues. The coils are my next step, as I replaced the plugs when I bought it but took the previous owners word on a recent coil/plug tune up so didn't replace them. I should've done it anyway when I realized the plugs looked original to the vehicle at 117k.

I'll get the coils replaced and do a fresh tune up and post back my update. Hopefully that solves the issue. I'm looking into doing a turbo install in the near future, but don't want to soak the money into it if there are any other costly repairs necessary.

 

[rogerrunnalls]

And? Plugs solved it?

 

[Gmctyphoon]

And? Plugs solved it?

So, on this forum and almost all forums there are dates for each post. Herethey are right under then name of the poster.

This thread was 6 years old..

If you come across an old thread like this one, it’s best to start a new thread of your own.

That said, the original guys problem could have been so many things.