LNF Engine hesistation
Thread Starter
New Member
Joined: 10-14-10
Posts: 52
Likes: 0
From: savannah
LNF Engine hesistation
Hello all,
I have a 2010 Cobalt SS with some pretty basic stuff, K&N intake, ZZP intercooler/piping, GMS1 upgrade, only 27k miles on the car.
back history:
bought in 2010, laid up in storage (exposed to elements) from 2013-2016, drove the car cross country and shipped it overseas. Minor problems with the car, heater core crack (replaced under warranty) and two GMS1 Bosch MAP sensors dying (I attribute this to the crappy aftermarket intake that came on the car when I got it). I plopped some KTP gas stabilizer in the car before I left and have sent money back home to have them perform regular oil changes, gas changes, driving, service, etc. (I don't believe this was done to my expectations or monetary contributions much to my chagrin)
During the cross country drive I cracked my intercooler and managed to epoxy it to survive the rest of the journey. Had a evap code which I managed to fix with a new purge solenoid (if you guys need the exact code I can pull from my computer when I get home).
Fast forward to two days ago, I noticed that I started losing power while driving, with a bit of engine hesitation without a drop in RPMs, after noticing the power loss I switched my display through the various menus, (cam angle, fuel/air) and noticed that the fuel air would spike from the regular 14.7 to 18 (maximum value on factory display) when the stutter would occur, followed by overcompensation of the ECU and stabilization back at 14.7. this would continue as I drove. I have noticed that it only occurs after extended driving of 30 minutes or more, leading me to believe it may be a fuel supply problem rather than an electrical/spark plug problem. A week prior to these issues I did have a couple codes (%%%%%% placeholder) for the EVAP system again, but I logged and cleared them and they haven't come back. Before I go my usual method of searching the internet and needlessly replacing parts until I fix it I figured id ask the community.
Thus far I have ordered new plugs, new fuel filter, and new EVAP purge solenoid (again...) and I intend to vacuum test my lines (unless that's not necessary).
Thoughts?
I have a 2010 Cobalt SS with some pretty basic stuff, K&N intake, ZZP intercooler/piping, GMS1 upgrade, only 27k miles on the car.
back history:
bought in 2010, laid up in storage (exposed to elements) from 2013-2016, drove the car cross country and shipped it overseas. Minor problems with the car, heater core crack (replaced under warranty) and two GMS1 Bosch MAP sensors dying (I attribute this to the crappy aftermarket intake that came on the car when I got it). I plopped some KTP gas stabilizer in the car before I left and have sent money back home to have them perform regular oil changes, gas changes, driving, service, etc. (I don't believe this was done to my expectations or monetary contributions much to my chagrin)
During the cross country drive I cracked my intercooler and managed to epoxy it to survive the rest of the journey. Had a evap code which I managed to fix with a new purge solenoid (if you guys need the exact code I can pull from my computer when I get home).
Fast forward to two days ago, I noticed that I started losing power while driving, with a bit of engine hesitation without a drop in RPMs, after noticing the power loss I switched my display through the various menus, (cam angle, fuel/air) and noticed that the fuel air would spike from the regular 14.7 to 18 (maximum value on factory display) when the stutter would occur, followed by overcompensation of the ECU and stabilization back at 14.7. this would continue as I drove. I have noticed that it only occurs after extended driving of 30 minutes or more, leading me to believe it may be a fuel supply problem rather than an electrical/spark plug problem. A week prior to these issues I did have a couple codes (%%%%%% placeholder) for the EVAP system again, but I logged and cleared them and they haven't come back. Before I go my usual method of searching the internet and needlessly replacing parts until I fix it I figured id ask the community.
Thus far I have ordered new plugs, new fuel filter, and new EVAP purge solenoid (again...) and I intend to vacuum test my lines (unless that's not necessary).
Thoughts?
The actual codes will be very helpful.
I can't help but think that boost leak is a good possibility since your intercooler cracked and the "crappy" intake. Does your A/F spike when you're hard on the throttle or idle?
I can't help but think that boost leak is a good possibility since your intercooler cracked and the "crappy" intake. Does your A/F spike when you're hard on the throttle or idle?
Thread Starter
New Member
Joined: 10-14-10
Posts: 52
Likes: 0
From: savannah
The intake and IC were replaced awhile back months before the problems started happening. Engine codes were p0442, p0445, p0689. After I logged and cleared the codes they haven't come back yet. Also the car has a new symptom, it will turn off for a fraction of a second while driving (engine, radio, everything)
I have replaced the evap purge valve 4 times in 115k miles.
As for the P0689, seems ignition related. But that is not a common code.
Also, make sure your battery is good. Several have reported that issue with an almost dead battery.
As for the P0689, seems ignition related. But that is not a common code.
Also, make sure your battery is good. Several have reported that issue with an almost dead battery.