2007 chevy aveo. bought the car still under warranty. engine starting knocking. took it back to chevy and they rebuilt it ( just to let you know i am a audi tech. so i've tried to diagnose this problem.) anyways after the engine has been rebuilt check engine light comes on. needs an O2 sensor. no big deal. check engine light comes on again. random misfire. i take it back they tell me it may need a coil which is not covered under my powertrain warranty. car never runs bad. and the check engine light only comes on at high rpm. (like trying to pass a car.) or sustained higher rpm like interstate driving 75 mph or so. same fault every time. random misfire/cylinder 1 misfire/cylinder 4 misfire. which on the coil pack 1 and 4 are together and 2 and 3 on the other. check all the connections everything is good. sprayed the wires down with water no arcs. so i replaced the plugs and the coil pack. still the same problem. high rpm misfire faults. any one have any ideas on this. the car never seems to run bad ever. is it possible its picking up a false misfire?
Gm has a problem with this from way back. double check your spark plugs and if they are not ac delcos, change them. ive seen this time and time again swearing, myself, that there is no way that the plugs would cause this issue. it always comes up with random misfire and usually another 1 or 2 codes misfire codes. put in ac delco, no more codes. let me know
There is a crankshaft position sensor that can cause this. Especially if the motor has been rebuilt. There is this procedure to follow straight out of my manual.
Crankshaft Position System Variation Learn
Important: If the crankshaft position variation learn procedure has not learned, a false misfire
could be detected and DTC P0300 may set. If sent here from DTC P0300, proceed with the
crankshaft position variation learn procedure.
1. Monitor the engine control module (ECM) for DTCs with a scan tool. If other DTCs are set,
except DTC P0300, or P0315, refer to Diagnostic Trouble Code (DTC) List - Vehicle for the
applicable DTC.
2. Select the crankshaft position variation learn procedure with a scan tool.
3. The scan tool instructs you to perform the following:
Vehicle must remain in Park or Neutral.
The scan tool monitors certain component signals to determine if all the conditions are met to
continue with the procedure. The scan tool only displays the condition that inhibits the
procedure. The scan tool monitors the following components:
4. Enable the CKP system variation learn procedure with the scan tool and perform the
following:
3.1. Accelerate to wide open throttle (WOT).
3.2. Release throttle when fuel cut-off occurs.
3.3. Observe fuel cut-off for applicable engine.
3.4. Engine should not accelerate beyond calibrated RPM value.
3.5. Release throttle immediately if value is exceeded.
3.6. Block drive wheels.
3.7. Set parking brake.
3.8. DO NOT apply brake pedal.
3.9. Cycle ignition from OFF to ON.
3.10. Apply and hold brake pedal.
3.11. Start and idle engine.
Vehicle must remain in Park or Neutral.
The scan tool monitors certain component signals to determine if all the conditions are met to
continue with the procedure. The scan tool only displays the condition that inhibits the
• Crankshaft position (CKP) sensors activity--If there is a CKP sensor condition, refer to
the applicable DTC.
• Camshaft position (CMP) signal activity--If there is a CMP signal condition, refer to the
applicable DTC.
• Engine coolant temperature (ECT)--If the engine coolant temperature is not warm
enough, idle the engine until the engine coolant temperature reaches the correct
4. Enable the CKP system variation learn procedure with the scan tool and perform the
Important: While the CKP variation learn procedure is in progress, hold the throttle at
WOT for 5 fuel-cutoffs. The learn procedure must determine there has been 5 fuel-cutoffs
to properly perform the test.
The scan tool displays Learn Status: Learned this ignition. If the scan tool indicates that
DTC P0315 ran and passed, the CKP variation learn procedure is complete. If the scan tool
indicates DTC P0315 failed or did not run, refer to DTC P0315. If any other DTCs set, refer to
Diagnostic Trouble Code (DTC) List - Vehicle for the applicable DTC.
6. Turn OFF the ignition for 30 seconds after the learn procedure is completed successfully.
The CKP system variation learn procedure is also required when the following service procedures
have been performed, regardless of whether or not DTC P0315 is set:
• Hold throttle while fuel cut-off occurs.
• An engine replacement
• An ECM replacement
• A harmonic balancer replacement
• A crankshaft replacement
• A CKP sensor replacement
Vehicle must remain in Park or Neutral.
The scan tool monitors certain component signals to determine if all the conditions are met to
continue with the procedure. The scan tool only displays the condition that inhibits the
3.12. Turn A/C OFF.
procedure. The scan tool monitors the following components:
temperature.
following:
• Accelerate to WOT.
• Any engine repairs which disturb the crankshaft to CKP sensor relationship.
procedure. The scan tool monitors the following components:
I also have problems when I reach the 50MPH, missfires occurs... I change the Plugs to AC Delco, still the same problem. Ideas????
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i will give it a shot. i have ngk v power copper plugs in it right now. i'll swing by the dealer and get the oem ones.
i'll stop by the dealer and pick some up. i have ngk v-power in it right now and i was pretty sure thats what the oem plug was for that car.
Wow! I am having the same problem with my 06 Aveo that has been rebuilt. I wished I had read this before I bought the spark plugs and had them replaced. If I don't change to the AC DELCOS, will it hurt to run my car?
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