987 All cylinders misfire
08-07-2022, 07:51 PM
#1
987 All cylinders misfire
Greetings all!
Got a 06 Boxster Base 5MT. Back in April, the CEL came on while driving with P2188—“System too lean at idle bank 1” and P2190—“System too lean at idle bank 2”. The car clearly didn’t run as well as it did before but otherwise drove normally. I cleaned the MAF sensor thoroughly with MAF cleaner and cleared the codes. This seemed to have fixed the issue.
Two months of driving later, the same codes came back, this time with a new one: P1095—“Air mass (HFM) ahead of throttle valve – implausible”. So I bought a new Bosch MAF senor from Amazon and swapped it on and changed the air filter. The car ran better than ever before afterwards and I thought the issue was resolved.
Two weeks later, while I was driving at ~50mph, the car suddenly started to shudder and suffered a massive loss of power. CEL also came on. Luckily I was just a few miles from home so I gently drove it back. When I got close to home the shudder and power loss seemed to have stopped, although the car behaved more like it got its first CEL back in April, running somewhat sluggish but otherwise normal.
I plugged in my Foxwell scanner and got the following trouble codes:
- P0300—Misfiring, checksum error
- P0301—Misfiring, cylinder 1
- P0306—Misfiring, cylinder 6
- P0302—Misfiring, cylinder 2
- P0304—Misfiring, cylinder 4
- P0303—Misfiring, cylinder 3
- P0305—Misfiring, cylinder 5
- P1133—Oxygen sensing adaptation FRAU bank 2 lower load range
- P2179—Oxygen sensing adaptation FRAU bank 2 lower load range
- P1126—Oxygen sensing adaptation FRAU bank 1 lower load range
- P2177—Oxygen sensing adaptation FRAU bank 1 lower load range
Could this indicate a problem with the oxygen sensors? Or is it something else? I’m leaning towards the new MAF sensor being faulty that was causing the issue. But it’s not even on there for two weeks and has the exact same part number as the old one. I might put the old MAF sensor on and test drive it but honestly I’m a little afraid to drive the car for now.
A few things to note:
- Previous owner claims he put on new spark plugs, which means they are about 5000 miles old now.
- Both times I pulled out the MAF sensor there was oil on it. However, my car doesn’t seem to have the telltale signs of AOS failure as it rarely smokes on startup and doesn’t burn oil.
Has anyone experienced similar issues? Any help is greatly appreciated.
Thanks in advance!
Got a 06 Boxster Base 5MT. Back in April, the CEL came on while driving with P2188—“System too lean at idle bank 1” and P2190—“System too lean at idle bank 2”. The car clearly didn’t run as well as it did before but otherwise drove normally. I cleaned the MAF sensor thoroughly with MAF cleaner and cleared the codes. This seemed to have fixed the issue.
Two months of driving later, the same codes came back, this time with a new one: P1095—“Air mass (HFM) ahead of throttle valve – implausible”. So I bought a new Bosch MAF senor from Amazon and swapped it on and changed the air filter. The car ran better than ever before afterwards and I thought the issue was resolved.
Two weeks later, while I was driving at ~50mph, the car suddenly started to shudder and suffered a massive loss of power. CEL also came on. Luckily I was just a few miles from home so I gently drove it back. When I got close to home the shudder and power loss seemed to have stopped, although the car behaved more like it got its first CEL back in April, running somewhat sluggish but otherwise normal.
I plugged in my Foxwell scanner and got the following trouble codes:
- P0300—Misfiring, checksum error
- P0301—Misfiring, cylinder 1
- P0306—Misfiring, cylinder 6
- P0302—Misfiring, cylinder 2
- P0304—Misfiring, cylinder 4
- P0303—Misfiring, cylinder 3
- P0305—Misfiring, cylinder 5
- P1133—Oxygen sensing adaptation FRAU bank 2 lower load range
- P2179—Oxygen sensing adaptation FRAU bank 2 lower load range
- P1126—Oxygen sensing adaptation FRAU bank 1 lower load range
- P2177—Oxygen sensing adaptation FRAU bank 1 lower load range
Could this indicate a problem with the oxygen sensors? Or is it something else? I’m leaning towards the new MAF sensor being faulty that was causing the issue. But it’s not even on there for two weeks and has the exact same part number as the old one. I might put the old MAF sensor on and test drive it but honestly I’m a little afraid to drive the car for now.
A few things to note:
- Previous owner claims he put on new spark plugs, which means they are about 5000 miles old now.
- Both times I pulled out the MAF sensor there was oil on it. However, my car doesn’t seem to have the telltale signs of AOS failure as it rarely smokes on startup and doesn’t burn oil.
Has anyone experienced similar issues? Any help is greatly appreciated.
Thanks in advance!
08-08-2022, 09:26 AM
#2
Instructor
My guess would be that oil has fouled the new MAF sensor after 2 weeks and is causing the same issue. If it's not getting a proper reading, then the whole engine would go haywire. Maybe try giving the MAF again and see if that solves the problem temporarily? If so, you need to track down the cause of the oil leak. AOS would be my 1st guess.
08-08-2022, 10:40 AM
#4
Nordschleife Master
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Misfires on all cylinders and previous lean DTC points to a clogged fuel system or low pressure. You really need to have your fuel pump tested for pressure. It could be clogged or malfunctioning. The fuel pumps are inside the fuel tanks.
Now, a quick and easy test: Clean and install the original MAF back on the car. Burn off all the current gasoline or drain to a very low tank (just above EMPTY), then add two cans of Seafoam. Drive it like you stole it - wide open throttle. Of course, drive safe and legal. Just don't drive it like grandma.
Run that for at least 15 miles. Then fill up with fresh Shell V Power.
Now, the car also needs to be evaluated with a proper scanner that can display LIVE data - particularly camshaft deviations and rough running index. This would help rule out any problems with the valve train and ignition timing. A Porsche PIWIS or Durametric can do this. Not sure about your Foxwell.
Now, a quick and easy test: Clean and install the original MAF back on the car. Burn off all the current gasoline or drain to a very low tank (just above EMPTY), then add two cans of Seafoam. Drive it like you stole it - wide open throttle. Of course, drive safe and legal. Just don't drive it like grandma.
Run that for at least 15 miles. Then fill up with fresh Shell V Power.
Now, the car also needs to be evaluated with a proper scanner that can display LIVE data - particularly camshaft deviations and rough running index. This would help rule out any problems with the valve train and ignition timing. A Porsche PIWIS or Durametric can do this. Not sure about your Foxwell.
Last edited by ZuffenZeus; 08-08-2022 at 10:44 AM.
The following users liked this post:
Chris MI 987 (08-10-2022)
08-08-2022, 10:36 PM
#5
Thank you all for your suggestions! Yesterday I unplugged the MAF sensor and gave it a spin. Got a CEL of course but guess what, no more misfire symptoms or codes. So I guess it's safe to isolate the problem to the MAF for now.
08-08-2022, 10:49 PM
#6
I accidentally put about 2 gallons of 89 during my last refueling. But I doubt it has to do with anything.
I use Shell almost exclusively.
Given that the car stopped misfiring when I unplugged the MAF, I think the fuel system is okay. I get Shell gas whenever I can. Do you know where I can find the proper values for such live data?
Could be. I read somewhere that it's normal to have some oil on the MAF although I don't know how much should be considered "normal". I took out the new MAF and there was a little bit of oil. Definitely not as much as the old one had. Given how big the misfire was (I could barely accelerate past 40mph) and the old MAF never gave me such issues, I thought the new MAF must have failed somehow and it was not just due to inaccurate readings caused by oil. Also I came across this thread on the 986 forum that mentions people getting bad MAF sensors lately. I think what I'll do next is to plug back the old MAF, drive it and see how soon the DTCs come back, while I source for a new MAF.
I use Shell almost exclusively.Misfires on all cylinders and previous lean DTC points to a clogged fuel system or low pressure. You really need to have your fuel pump tested for pressure. It could be clogged or malfunctioning. The fuel pumps are inside the fuel tanks.
Now, a quick and easy test: Clean and install the original MAF back on the car. Burn off all the current gasoline or drain to a very low tank (just above EMPTY), then add two cans of Seafoam. Drive it like you stole it - wide open throttle. Of course, drive safe and legal. Just don't drive it like grandma.
Run that for at least 15 miles. Then fill up with fresh Shell V Power.
Now, the car also needs to be evaluated with a proper scanner that can display LIVE data - particularly camshaft deviations and rough running index. This would help rule out any problems with the valve train and ignition timing. A Porsche PIWIS or Durametric can do this. Not sure about your Foxwell.
Now, a quick and easy test: Clean and install the original MAF back on the car. Burn off all the current gasoline or drain to a very low tank (just above EMPTY), then add two cans of Seafoam. Drive it like you stole it - wide open throttle. Of course, drive safe and legal. Just don't drive it like grandma.
Run that for at least 15 miles. Then fill up with fresh Shell V Power.
Now, the car also needs to be evaluated with a proper scanner that can display LIVE data - particularly camshaft deviations and rough running index. This would help rule out any problems with the valve train and ignition timing. A Porsche PIWIS or Durametric can do this. Not sure about your Foxwell.
My guess would be that oil has fouled the new MAF sensor after 2 weeks and is causing the same issue. If it's not getting a proper reading, then the whole engine would go haywire. Maybe try giving the MAF again and see if that solves the problem temporarily? If so, you need to track down the cause of the oil leak. AOS would be my 1st guess.
Last edited by scarletmoon; 08-08-2022 at 10:53 PM.
08-09-2022, 06:31 AM
#7
Instructor
Yes I think you're on the right track with the MAF. Personally doesn't seem like a fuel issue to me, especially if you're been using quality Shell. A couple gallons of 89 is not going to cause severe misfire issues like this.
The following 2 users liked this post by palestar:
scarletmoon (08-10-2022),
Schwinn (08-11-2022)
