Specs: Saab 07 Aero 2.8 84k miles (I have put on about 7k)
Parts Replaced: Battery (was failing over winter), Vacuum lines from master cylinder, spark plugs ((NGK #1959 (Double Platinum) gapped 0.035), all 6 coils (bosch),
Previous History I have found: Car has had its upper intake gaskets replaced (I could see fel-pro which probably aren't stock). Previous owner also had a fuel injector cleaning at pepboys a few years back. Also 3 back coils were replaced (no clue when) plugs didn't look old at all. I suspect this misfire issue was happening in the past.
History: During the winter while warming up, car was occasionally shutting off (no codes). It would also happen sometimes at stop signs. Eventually I got misfire codes while driving (p0306 p0305 p0304 0303 p0301 p0300). So I changed the plugs and the car ran fine for a week then misfires again. When changing the plugs, I noticed the previous owner changed the back 3 coils with non Bosch ones. So figured it was probably the coils. Changed out all the coils and made the gaps the smallest gap size as per the sticker on car (0.035). Car ran fine for few days and again misfires while on the highway. So I thought it was probably a bad connection at the coil wire since the car was running perfect for a few days. Took each coil and depinned and cleaned them 1 by 1 all 6 oil connections. Used some fine sandpaper and and de-xoit dn5. I also sprayed the pin connectors for the ecm(*see for more on why I cleaned each wire). Car ran perfect for about a week even in heavy traffic. Then one night coming back from the city, we pulled up to a spot to get a snack and the car shut off while in drive. The next day it also shut off while I was leaving a drive-thru and on then while on the highway, boom blinking misfires and non blinking again (this data log is used in the misfire charts). While the misfires were happening on the highway, I looked at torque and noticed that my short and long term fuel trim were no longer adjusting itself and my evap pressure was no longer adjusting either and the o2 sensors were also flat lined. I am not sure if once the car detects misfires is this has anything to do with limp mode perhaps?!?
Following day, I needed to move the car into the driveway. I turned on the car, it was running terrible with check engine light as expected. Moved the car before it was even able to fully warm up. Then shut the car off popped the hood. It was at that point that I heard the electronic Boost pressure control valve (179a) still clicking with the car off (**see video). I have not noticed and issue with the boost.
* Reason I decided to clean the connectors was because over the winter my headlight, my fog light (even my exterior temp sensor) was not always turning on and if you hit it, it would turn on aka bad electrical connection. So I depinned the connector wiring by the window washer fluid and cleaned all the wires. Never had an issue after that with the lights again. The pins for looked clean, no visible rust or gunk but there must have been some gunk on there invisible to the eye.
** ((Video of Boost pressure control valve (179a) Clicking While is Car Off (
)
Thoughts and analysis:
I downloaded and plotted my good and bad rides from Torque Pro to examine (See attached). When the misfires happened on the highway, torque stopped showing changes to long and short term fuel trim. The o2 sensors seemed to also flat line and the evap was no longer fluctuating like when the car was running normal.
I used torque for my logging because it was much easier to do with the tablet and bluetooth dongle. The car stopped misfiring for over a week and then just did again.
The three times I have disconnected the coils and plugs and ecu (ME9), afterwards the car has worked normally meaning no misfires. Which makes me believe the issue is electronic but that is just me thinking out loud. After everything that happened and looking at the torque data seems like it could be my 02 sensors and/or something with the evap because data stops changing immediately after the misfires. :roll:
Parts Replaced: Battery (was failing over winter), Vacuum lines from master cylinder, spark plugs ((NGK #1959 (Double Platinum) gapped 0.035), all 6 coils (bosch),
Previous History I have found: Car has had its upper intake gaskets replaced (I could see fel-pro which probably aren't stock). Previous owner also had a fuel injector cleaning at pepboys a few years back. Also 3 back coils were replaced (no clue when) plugs didn't look old at all. I suspect this misfire issue was happening in the past.
History: During the winter while warming up, car was occasionally shutting off (no codes). It would also happen sometimes at stop signs. Eventually I got misfire codes while driving (p0306 p0305 p0304 0303 p0301 p0300). So I changed the plugs and the car ran fine for a week then misfires again. When changing the plugs, I noticed the previous owner changed the back 3 coils with non Bosch ones. So figured it was probably the coils. Changed out all the coils and made the gaps the smallest gap size as per the sticker on car (0.035). Car ran fine for few days and again misfires while on the highway. So I thought it was probably a bad connection at the coil wire since the car was running perfect for a few days. Took each coil and depinned and cleaned them 1 by 1 all 6 oil connections. Used some fine sandpaper and and de-xoit dn5. I also sprayed the pin connectors for the ecm(*see for more on why I cleaned each wire). Car ran perfect for about a week even in heavy traffic. Then one night coming back from the city, we pulled up to a spot to get a snack and the car shut off while in drive. The next day it also shut off while I was leaving a drive-thru and on then while on the highway, boom blinking misfires and non blinking again (this data log is used in the misfire charts). While the misfires were happening on the highway, I looked at torque and noticed that my short and long term fuel trim were no longer adjusting itself and my evap pressure was no longer adjusting either and the o2 sensors were also flat lined. I am not sure if once the car detects misfires is this has anything to do with limp mode perhaps?!?
Following day, I needed to move the car into the driveway. I turned on the car, it was running terrible with check engine light as expected. Moved the car before it was even able to fully warm up. Then shut the car off popped the hood. It was at that point that I heard the electronic Boost pressure control valve (179a) still clicking with the car off (**see video). I have not noticed and issue with the boost.
* Reason I decided to clean the connectors was because over the winter my headlight, my fog light (even my exterior temp sensor) was not always turning on and if you hit it, it would turn on aka bad electrical connection. So I depinned the connector wiring by the window washer fluid and cleaned all the wires. Never had an issue after that with the lights again. The pins for looked clean, no visible rust or gunk but there must have been some gunk on there invisible to the eye.
** ((Video of Boost pressure control valve (179a) Clicking While is Car Off (
Thoughts and analysis:
I downloaded and plotted my good and bad rides from Torque Pro to examine (See attached). When the misfires happened on the highway, torque stopped showing changes to long and short term fuel trim. The o2 sensors seemed to also flat line and the evap was no longer fluctuating like when the car was running normal.
I used torque for my logging because it was much easier to do with the tablet and bluetooth dongle. The car stopped misfiring for over a week and then just did again.
The three times I have disconnected the coils and plugs and ecu (ME9), afterwards the car has worked normally meaning no misfires. Which makes me believe the issue is electronic but that is just me thinking out loud. After everything that happened and looking at the torque data seems like it could be my 02 sensors and/or something with the evap because data stops changing immediately after the misfires. :roll:
