I drove it with the scanner running and watched it the rail pressure. When I accelerate slightly harder than grandma mode, I get what I would describe as a miss. Doesn't do it every time, but it's reasonably predictable. While testing, I could see no correlation between the fuel pressure on the rail and the miss. That could be because the scanner isn't sampling often enough, or it could be that it's not the issue.

Maybe it's not the fuel pumps at all? With readings into the 12's MPa when it's running, that's over 1700 psi, which I would guess is correct?

I would suspect dirty injector. Have you run injector cleaner?

Yes, didn't seem to change anything.

Can you realtime monitor your smooth running (forgot there actual term) on All cylinders. If you can pin down one cylinder you may be able to pinpoint the cause

I think I can, I'll check.

Thanks for the input!

I’m beginning to think it’s not fuel related at all. I put it in neutral and rev the engine multiple times and it never misses. I put the shift mode into manual and accelerated moderately in 1st, no issues, shifted to 2nd, up to 4,000, no issues, 3rd gear, no issues. Put it back in automatic and I get the miss feeling.

Any ideas? Would a vacuum leak be a possibility?

andrew- "run unrest"


siggy- the DME knows what kind of load the engine is seeing, when it is in gear it may be using differnet 'demand maps' which may be calling for different fuel pressures.



Not sure, but a caution that these can have complexities.


Still, you really need something (INPA, etc) that is telling you what this "miss feeling"really is....


https://www.youtube.com/watch?v=Bo-qweh7nbQ

I never remember that term because it's not used in my scanners. They call it something like smooth running values. Good to see the BMW software name for it though so I know what other people are talking about.

I still don't remember *exactly* what my scanners call it.

I've been trying to get ISTA+ to work for a month now. I actually paid for it, which later, I found the note in the readme that said it's free and if you paid for it, ask for your money back, but I have never been able to get it to connect to the car. Of course, zero help from the place I bought it from. I have the K+DCAN cable with the switch. Windows seems to see that fine but I cannot get it to connect to the car.

At some point, I found the site that had all the files, from the source, I'm guessing. I had just bought the download, so I didn't bookmark the free site.

Fast forward a month, I deleted all my current install, and thought I'd start over using the current files online but now I can't locate them. I thought they were all on a file sharing system somewhere, with all the data files too, but I can't find them now. All internet searches bring up everyone wanting $69 for it.

Any idea where to download ISTA+?