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View Full Version : 2001 740iL P0172 Code and Weird Symptoms



01740iL1985
02-15-2016, 05:28 PM
So today driving to work everything was going great and then all of the sudden the SES light flashed about 5 times and went out. Then seconds later did the same thing, stayed on and then it was like the car was running on 4 cylinders.

So, I pulled over and put it in park. The car had a terrible idle and was shaking pretty good. A little bit of gas and the misfire did not go away.

Cut the car off and restarted. The miss was gone and all back to normal. So I continued the drive to work. Had the same thing happen again a few miles down the road. Got to work cut it off and back on and again misfire was gone.

Started it to leave work and got the same thing again. Few miles in, everything running smooth, SES light flashes twice and the rough running begins again. I have diagnostics but won't be able to plug it up until this weekend. So, I went to the local advance and got P0172 for a code. System lean.....I think.

Just wondering if anyone has had this same issues before and what resolved it. I hate not being able to plug it up right away, but figured someone has had this happen before. Also, startup is fine no misfire at all. And it runs fine in the beginning of a 15-20 mile trip. Only after about 5 miles do the symptoms show up.

Also just for knowledge of the car below is a list that I have already gone through and parts replaced....

Intake removed and gaskets replaced on the bottom and front and back about 8,000 miles ago.

OSV bypassed using a catch can about 6,000 miles ago.

New MAF sensor about 1,500 miles ago.

No vacuum leaks.

Coils are good.

New plugs about 12,000 miles ago....guess I shouldn't call those new lol.

New fuel pump about 9,000 miles ago.

Original cats.

Original O2 sensors.

Car has been running great ever since new MAF was installed took care of my hesitation at idle that I was having.

Any help or suggestions would be greatly appreciated.

Timm
02-16-2016, 05:23 AM
Sounds like your catalytic converter(s) are breaking up and blocking the gas-flow - anything like this:

http://www.meeknet.co.uk/e31/E31_840ci_Misfire_At_Full_Throttle.htm

01740iL1985
02-16-2016, 06:38 PM
Actually getting totally different codes. Seems like a coil pack again :/.

I had many cylinder misfires after yesterday's mishaps so I plugged it up and cleared the codes and drove to get what the initial problem was.

Drove the car to create same results. Again at about 3500 RPMS the ses light flashes and this time I let out of the throttle and it stopped flashing and went out. Made this happen 4 times on the drive.

I got 3 errors.
http://uploads.tapatalk-cdn.com/20160216/e6387a4cfb63dfe9f2332e4445358dab.jpg
This one is secondary air system error. I'm thinking this is random due to a faulty coil pack.

http://uploads.tapatalk-cdn.com/20160216/35be4aa1441565d07ef75c7df0962085.jpg
This one is misfire detected.

http://uploads.tapatalk-cdn.com/20160216/bb8694254bd824ade812e22f76184be1.jpg
This one is misfire detected cylinder 2.

Pulled the plugs all looked good. So again I'm assuming coil pack. Had similar symptoms when one went a while back. Different cylinder than this time. Do I sound like I'm on the right track?

01740iL1985
02-24-2016, 09:08 PM
Just to follow up.....it was coil pack. Bought new and replaced no more issues.