Rough Idle, Acceleration miss
Railroader
11-06-2014, 07:27 PM
1996 Chevy Corsica Basic 3.1 150,000 miles
Vin: 1G1LD55M3TY272843
PO300 Random Misfire Code
Somewhat rough idle, engine hesitates, Misses, sputters, when Throttle opened fast
Here is what I have done so far.
Replaced Plug Wires
Replaced Plugs
Replaced Coolant Temp Sensor
Checked for Vacuum Leaks
Replaced PVC Valve Tube Assembly
Did Vacuum Test (15-hg Steady) (Snap throttle open test) go's to 5, 0, returns to 15-hg, (Deceleration: Goes to 25 or so then returns to 15 -hg
Replaced Fuel Filter
Replaced Fuel Pressure Regulator
Replaced Both Oxygen Sensors
2 Out of 3 Coils Replaced (did swap coils around, no change)
Checked Fuel Pump Pressure 38 to 40lbs
Things I have not done
Have not Checked Injectors
Have not done a close inspection to see if antifreeze is leaking around the intake manifold (Not readily apparent)
Have not checked EGR Valve (no codes)
Have not checked MAF Sensor (no codes)
Have not checked MAP sensor (no codes)
Thanks for any suggestions
Vin: 1G1LD55M3TY272843
PO300 Random Misfire Code
Somewhat rough idle, engine hesitates, Misses, sputters, when Throttle opened fast
Here is what I have done so far.
Replaced Plug Wires
Replaced Plugs
Replaced Coolant Temp Sensor
Checked for Vacuum Leaks
Replaced PVC Valve Tube Assembly
Did Vacuum Test (15-hg Steady) (Snap throttle open test) go's to 5, 0, returns to 15-hg, (Deceleration: Goes to 25 or so then returns to 15 -hg
Replaced Fuel Filter
Replaced Fuel Pressure Regulator
Replaced Both Oxygen Sensors
2 Out of 3 Coils Replaced (did swap coils around, no change)
Checked Fuel Pump Pressure 38 to 40lbs
Things I have not done
Have not Checked Injectors
Have not done a close inspection to see if antifreeze is leaking around the intake manifold (Not readily apparent)
Have not checked EGR Valve (no codes)
Have not checked MAF Sensor (no codes)
Have not checked MAP sensor (no codes)
Thanks for any suggestions
maxwedge
11-06-2014, 07:45 PM
See how it feels with the maf disconnected.
Railroader
11-06-2014, 08:47 PM
It looks like the Intake Manifold is leaking, pool of antifreeze in the valley under the thermostat, and this is a known problem with the 3.1 engine. guess it is gasket change time. Did not appear to be any antifreeze getting into the oil though. Thanks
Railroader
03-01-2015, 05:37 PM
That problems fixed, replaced intake manifold gaskets. Got another problem now.
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