95 540/6 running bad again

[barry 90 525i]

Car is running really bad again. After i changed the fuel filter the car ran normal for a couple of days, then started doing it's thing again. CEL comes on when just cruizing down the road and at idle. If u give it a little power it will clear up and run great. Sometimes it feels like it has no power on acceleration, but most of the time it will clear up. At idle it sounds like a 4 cylinder. Also at slow speeds when u let off the gas the power steering feels like it is binding, like the engine is not turning fast enough. Then all of a sudden it will run great for a day, but go back to running bad. Also my mpg is down by at least 2. Went and changed the fuel filter again, but no help. It seems to be fuel related. I changed MAF with my 540/a, no difference. Anyone have a idea?

[Rus]

Have you checked the fuel pressure? A failing pump could be the issue.

[Paul in NZ]

540? why does your name and sig indicate a 525?

[barry 90 525i]

Because i used to have one and have not changed it.

[barry 90 525i]

I did change it out with the one from my other 540 because it seems like fuel pressure but there was no change.

[Rus]

You say your CEL lights up. Can you read the codes that it stores? That will generally help with diagnosis. I remember when my 535 had low fuel pressure, it would throw an O2 sensor code because of a lean mixture under throttle. You 540 should be able to output the code for you.

[barry 90 525i]

No, i have tried many times to pick up the codes. Ive heard some cars for whatever reason the stomp test does not work.

[bubba966]

Stomp test should work just fine. Seems that not everyone is successful in doing it though. Most people apparently don't do it fast enough.

[barry 90 525i]

Well i have tried many times as fast as possible. I dont know how i could do it any faster.

[bubba966]

Your CEL isn't burnt out, right? And you're sure you've got the key turned over to the right position? I forget if you need position 1 or 2 as I've not bothered with it much as I've got a code reader.

Have you been able to get it to work on any other E34? It works fine on my M-Sport (9/95 build) as well as a friends '95 525iT (6/94 build).