Hi all, brand new member here! Go easy on me...
I drove my 2008 Escalade ESV about a couple weeks ago down the street, and the check engine light comes on (flashing), followed by the dreaded Stabilitrak error. The engine is very choppy and shaky, especially at low RPMs. My OBD2 shows code P0300 - engine misfire, multiple/random cylinders. OBD2 data shows misfires on cylinders 2 and 4.
In the meantime, I've done quite a bit of research on this. I'm not a mechanic, but I'm also not afraid to get my hands dirty, and have done some of my own car repairs.
So that being said, this is what I've done so far:
1. Replaced all 8 spark plugs and spark plug wires with AC Delco. Cleared codes. Started engine - same code P0300 returns, with misfires on 2/4.
2. Swapped 2/4 coils with 1/3. Cleared codes. Started engine - same code returns, misfires on 2/4.
3. Checked positive electrical signal to fuel injectors. When key is in ON position, there is a constant signal. Seems good to me.
4. Checked negative electrical signal to fuel injectors from ECM. When engine is started and running, I do see a fast "flashing" signal, which is what I would expect.
5. Removed fuel rail and all fuel injectors. Cleaned injectors by soaking them in fuel injector cleaner, and also blowing carb cleaner through them under charge. Although the cleaner was quite dark in color after I was done, they now appear to be very clean with no problems. Swapped injectors on 2/4 with 1/3 to be sure. Cleared codes, started engine - same code P0300 returns, with misfires on 2/4.
6. Removed passenger side valve cover. Rocker arms look good. I removed the arms and pulled out the push pins. Straight as an arrow. I have not yet put the rocker arms and push pins back in and tested, but am expecting the problem is still there.
So what else should I try? The only other things I can think of that it could be are:
1. Bad electrical connection somewhere.
2. Bad ECM.
Am I missing anything? Thank you so much for your help!
I drove my 2008 Escalade ESV about a couple weeks ago down the street, and the check engine light comes on (flashing), followed by the dreaded Stabilitrak error. The engine is very choppy and shaky, especially at low RPMs. My OBD2 shows code P0300 - engine misfire, multiple/random cylinders. OBD2 data shows misfires on cylinders 2 and 4.
In the meantime, I've done quite a bit of research on this. I'm not a mechanic, but I'm also not afraid to get my hands dirty, and have done some of my own car repairs.
So that being said, this is what I've done so far:
1. Replaced all 8 spark plugs and spark plug wires with AC Delco. Cleared codes. Started engine - same code P0300 returns, with misfires on 2/4.
2. Swapped 2/4 coils with 1/3. Cleared codes. Started engine - same code returns, misfires on 2/4.
3. Checked positive electrical signal to fuel injectors. When key is in ON position, there is a constant signal. Seems good to me.
4. Checked negative electrical signal to fuel injectors from ECM. When engine is started and running, I do see a fast "flashing" signal, which is what I would expect.
5. Removed fuel rail and all fuel injectors. Cleaned injectors by soaking them in fuel injector cleaner, and also blowing carb cleaner through them under charge. Although the cleaner was quite dark in color after I was done, they now appear to be very clean with no problems. Swapped injectors on 2/4 with 1/3 to be sure. Cleared codes, started engine - same code P0300 returns, with misfires on 2/4.
6. Removed passenger side valve cover. Rocker arms look good. I removed the arms and pulled out the push pins. Straight as an arrow. I have not yet put the rocker arms and push pins back in and tested, but am expecting the problem is still there.
So what else should I try? The only other things I can think of that it could be are:
1. Bad electrical connection somewhere.
2. Bad ECM.
Am I missing anything? Thank you so much for your help!