2007 Chevy Cobalt E85 Fuel, Engine knock, check engine ligh

Tiny
MONKEYSTONEART
  • MEMBER
  • 2007 CHEVROLET COBALT
Engine Mechanical problem
2007 Chevy Cobalt Engine Size unknown Wheel Drive Type unknown Automatic 40000 miles

This is a rental car to start with, got it 2 days ago, my fiancee filled up a 3/4 tank with E85 fuel and since then the vehicle has a knock to it (it struggles to when at idle) the gears seem to slip when accelerating (it feels as though it jerks when first accelerating) The check engine light has come on and has stayed on! Is this something I should be really worried about or could it be caused by the E85 fuel? Please help! Thank You!
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Saturday, February 23rd, 2008 AT 12:02 PM

3 Replies

Tiny
DENNYP
  • EXPERT
We need to know what code is stored in the computer. If you don't have less than 1/8 tank regular fuel and fill with E85, then it will cause problems.
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Saturday, February 23rd, 2008 AT 3:57 PM
Tiny
THE FACTORY MAN
  • MEMBER
A car that can use E-85 fuel has a sensor that determines what type of fuel is in the tank. I does not make a differance when and with what you fill the vehicle with. Are you sure the car is E-85 compatable?
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Monday, March 3rd, 2008 AT 10:32 AM
Tiny
DENNYP
  • EXPERT
#05-06-04-035C: Usage of E85 Fuels in GM Vehicles - (Jul 30, 2007)

Subject: Usage of E85 Fuels in GM Vehicles

Models: 1997-2008 GM Passenger Cars and Trucks (including Saturn)

2003-2008 HUMMER H2

2006-2008 HUMMER H3

1997-2008 Isuzu NPR Commercial Medium Duty Trucks

2005-2008 Saab 9-7X

This bulletin is being revised to add the 2008 model year and additional engines with E85 capability. Please discard Corporate Bulletin Number 05-06-04-035B (Section 06 -- Engine/Propulsion System).

Customer Interest in E85 Fuel
As the retail price of gasoline increases, some locations in the country are seeing price differentials between regular gasoline and E85 where E85 is selling for substantially less than regular grade gasoline. One result of this is that some customers have inquired if they are able to use E85 fuel in non-E85 compatible vehicles.

Important: Only vehicles designated for use with E85 should use E85 blended fuel.

E85 compatibility is designated for vehicles that are certified to run on up to 85% ethanol and 15% gasoline. All other gasoline engines are designed to run on fuel that contains no more than 10% ethanol.

Notice: Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

Using E85 Fuels in Non-Compatible Vehicles
General Motors is aware of an increased number of cases where customers have fueled non-FlexFuel designated vehicles with E85. Fueling non-FlexFuel designated vehicles with E85, or with fuels where the concentration of ethanol exceeds the ASTM specification of 10%, will result in one or more of the following conditions:

Lean Driveability concerns such as hesitations, sags and / or possible stalling.

SES lights due to OBD codes.

Fuel Trim codes P0171 and / or P0174.

Misfire codes (P0300).

Various O2 sensor codes.

Disabled traction control or Stability System disabled messages.

Harsh / Firm transmission shifts.

Fuel system and / or engine mechanical component degradation.

Notice: Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

If the dealer suspects that a non-FlexFuel designated vehicle brought in for service has been fueled with E85, the fuel in the vehicle's tank should be checked for alcohol content with tool J 44175. If the alcohol content exceeds 10%, the fuel should be drained and the vehicle refilled with gasoline - preferably one of the Top Tier brands.

Repairs to non-FlexFuel vehicles that have been fueled with E85 are not covered under the terms of the New Vehicle Warranty.

A complete list of GM s FlexFuel vehicles can be found in this Service Bulletin, or at www. Livegreengoyellow. Com.

E85 Compatible Vehicles
The only E85 compatible vehicles produced by General Motors are:

2000-2002 S-Series pickups with 2.2L (VIN 5- RPO L43)

2002-2005 full-size pickups and utilities with 5.3L (VIN Z -- L59)

2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe with 5.3L (VIN Z -- RPO L59)

2006-2007 Chevrolet Impala, Monte Carlo with 3.5L (VIN K -- RPO LZE)

2007 Chevrolet Avalanche, Suburban, Tahoe with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

2007 Chevrolet Express, GMC Savana with 5.3L (VIN Z-- RPO L59)

2008 Chevrolet Impala with 3.9L (VIN 3-- RPO LZG)

2006 GMC Sierra, Yukon, Yukon XL with 5.3L (VIN Z -- RPO L59)

2007 GMC Yukon, Yukon XL with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

2007 Saturn Relay, Buick Terraza, Chevrolet Uplander, Pontiac Montana SV6 (Canada Only) with 3.9L (VIN W -- RPO LGD)

Notice:

Only vehicles that are listed in the E85 Compatible Vehicles section of this bulletin and/or www. Livegreengoyellow. Com are E85 compatible.

All other gasoline and diesel engines are NOT E85 compatible.

Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

Repairs to non-FlexFuel vehicles that have been fueled with E85 are not covered under the terms of the New Vehicle Warranty.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
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Monday, March 3rd, 2008 AT 10:55 AM

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