2004 X5 4.4i Stuttering on acceleration issues need some assistance from the pro's!

[Johnny_5]

So, a few days ago, I was out running errands and car has no issues whatsoever but, on my way, back home is when I noticed that the X5 would studder on acceleration at around 2k RPM. Was having a hell of a time on the freeway and inside roads. I haven't had any chance to go over it yet but figured I post to see if anyone else experienced this. I did confirm its doing the same thing today when I took it around the block.

I'll probably try cleaning out the air flow sensor and change out the spark plugs but don't want to just start changing things out randomly. No check engine lights.

Any advice would be greatly appreciated.

[andrewwynn]

Scan for error codes first. Can be a dozen things.

Plugs/maf won’t hit suddenly and dramatically.

A guess would be cps as that's been the main culprits for me on m62tu.

You prob have the n62 which put the cps in the back i don't know if the different type has similar failure modes but with twice as many twice the chance of one messing up.

Miles on the odo?

–awr–

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[workingonit]

After I replaced a bad fuel pump, following complete failure, in mid-October, my X started to experience a stutter/stall when driving, on sharp turns or curves, or on change of direction (reversing to going forward). Problems I'd never had before the old pump died. Plus, my previously lean fuel trims became rich, even after resetting adaptations and the MAF. See this thread https://xoutpost.com/bmw-sav-forums/x5-e53-forum/116417. By the end of Oct, Post #63 https://xoutpost.com/1247122-post63.html, I had missed the inspection deadline, so I decided to work slowly to figure what's wrong, and not damage my bad shoulder doing so.

I haven't progressed on solving the problem yet, mostly due to health (my shoulder is better, but the Dr. said it might/might not heal some more, by itself, but without surgery, it will never get to above 75% useful...I opted not to get surgery), but now have all my tools & parts gathered to begin the work anew

• 1) drain the tank, filter the old fuel (possibly with loose particles from Cataclean usage),
• 2) reinstall the new Hella pump (or even a $69 Amazon pump, if I see a problem with the Hella from RockAuto),
• 3) remove the old fuel filter and FPR, replacing them with a new Hengst assembly,
• 4) replace all the fuel and vacuum lines,
• 5) retest the fuel pressure afterwards (new pressure tester)

.

Last month (2-3-2026), I ran it in the driveway, justto see if anything had changed by itself. I didn't check the fuel pressure, nor vacuum at the F-connector, but it started up instantly, and I ran it for about 30 minutes, letting the O2 sensors heat up, and the engine running at operating temperature for half that time (after sitting unused for months).

The fuel trims stayed normal (for a change), with the LTFTs at zero, and the STFTs around +/- 1-3. Not at all what I last saw. The MAF at 700rpm read 3.6gm/s to 4.2gm/s, also better than normal. O2 sensors were fine, with the front sensors on point immediately, while it took 15-20 minutes for the rear sensors to act right. Overall, I was pleased.

Since there was no hesitation whenever I pressed the accelerator, I'm assuming that the cause for zero pressure at the Schrader valve, last time I was testing, must be due to a restriction in the 5-ft extension hose, and/or the old fuel pressure tester gauge I was using.

So, Johnny_5, I'll be watching your thread for insights that might pertain to my X's situation, Good Luck.

[TriX5]

FWIW, A while back I had issues/stumbles on acceleration which got worse quite quickly (could be a year or two ago). No codes, but the problem always got worse when the engine was warm. I guessed that at 170K it would not hurt to replace the coils. Fixed the problem.

[Clockwork]

My E46 (M54 engine) had a similar issue where it stumbled at idle or just a few hundred rpm more. It was a Cam Shaft Position sensor.

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