N54 thas an odd surging/stuttering under heavy throttle.

[lochness_monster]

Disclaimer, I copied these words because I couldn't describe it any better.

The car is 2010,an automatic, and if I am in, for example, third gear at 40 MPH and I just use the engine to accelerate to 60 (no downshift), the power delivery will stutter. It feels like slipping (but RPMs are not rising) so it must be something cutting out in the power delivery. I shut off traction control to rule that out, and it still stutters. I should add that the car starts and runs perfectly EXCEPT for the surging/stuttering at 3,000-4,500 RPM.

Ideas? I tried search, but the terminology is hard to match, and there are so many types of misses and stutters that are different.

Thanks.

[iEuropa]

Some questions to help rule out possibilities:

To your knowledge:

1. Miles on the car?

2. Last time spark plugs were changed?

3. Last time the coil packs were changed?

4. Last time the intakes were cleaned (walnut blasted)?

5. Have the injectors been changed?

6. Has the HPFP been changed before?

7. Have you had the car in for service or changed anything recently.

[Stewy_604]

^^^ Good starting points to try and discover the root of the problem. Could be something as simple as bad plugs, or a dirty fuel filter. Start with the easy things first and see if you can chase the problem. Any fault codes?

[lochness_monster]

To your knowledge:

1. Miles on the car? 2010 with 80k

2. Last time spark plugs were changed? not sure, just bought car last week

3. Last time the coil packs were changed? not sure, is this a potential DIY

4. Last time the intakes were cleaned (walnut blasted)? this sounds pricey??

5. Have the injectors been changed?

6. Has the HPFP been changed before? how to find out? just bought car

7. Have you had the car in for service or changed anything recently. no

[lochness_monster]

Any recommendations for a shop in the twin city area??

[iEuropa]

Originally Posted by lochness_monster

To your knowledge:

1. Miles on the car? 2010 with 80k

2. Last time spark plugs were changed? not sure, just bought car last week

3. Last time the coil packs were changed? not sure, is this a potential DIY

4. Last time the intakes were cleaned (walnut blasted)? this sounds pricey??

5. Have the injectors been changed?

6. Has the HPFP been changed before? how to find out? just bought car

7. Have you had the car in for service or changed anything recently. no

Start with changing the spark plugs. If that doesn't fix it try having the intake cleaned. You can do both of those DIY if you are mechanically inclined. Plugs are like ~$100 to change, a walnut blast can be done including the cost of the equipment for like $400.

Coil packs are also DIY. Injectors are harder to change. If you don't have a car fax or similar there is not great way to know if the HPFP has been changed but I doubt that is the problem.

These cars are much more expensive to keep than a honda or vw if you cannot DIY at least some projects. I have a master mechanic friend with a lift so I do all my work myself.

I bought my car after it had sat for two years with essentially no carfax. (MAJOR risk, although not a total mistake.) I used to misfire so hard that I would get a limp mode. I changed the spark plugs and walnut blasted, and now the car is happily tearing around in a stage 1 MHD tune. So there is a good chance that's all she needs.

[Dackelone]

First, you need to check for codes thrown or about to log a code. You need a scan tool that can read shadow codes, not just OBD-II generic codes.

It really sounds like you have a misfire going on. Could be bad/worn plugs(they should be changed every 30K to 45K, you might start there) or maybe a bad coil. Of course a miss could also mean a bad injector or spray pattern - but that's not so common.

Could also be something as simple as bad fuel quality. Try switching fuel brand for a few tanks.

What about the HPFP ? Has that been changed?

You really need to have the codes read - before you dive too deep into this issue.

[lochness_monster]

Shadow codes? I'll have to search and read about that.

So JB4 or COBB will only read OBD-II generic codes is that correct?

thank you for your patience

[Dackelone]

Originally Posted by lochness_monster

Shadow codes? I'll have to search and read about that.

So JB4 or COBB will only read OBD-II generic codes is that correct?

thank you for your patience

No, I think both of those will read all bmw codes. But if you had a cheap OBDII code reader, those normally only read the basic generic codes. Or you could use Carly app with their dongle to read all bmw codes.