Hesitation and code P0300 HC
Thread Starter
Instructor
Joined: Dec 2005
Posts: 100
Likes: 0
From: Austin, TX
Hesitation and code P0300 HC
At slow speeds under load, I get a strange hesitation. For example, if I'm in 3rd gear at 20 mph and give half throttle, the car accelerates very slowly. The weird thing is, if I let off the gas, then get back on it, the car accelerates as it should. I know P0300 is a misfire code, but I can't actually feel a noticeable misfire. Just hesitation.
I filled up with Chevron and haven't driven the car in two weeks. Maybe it's a bad tank of gas? Also, the previous owner installed some NGK plugs not that long ago. I pulled one of them to diagnose another issue unrelated to this one, and it looked fine. The plug wires look new too. With the recent switch in gas formulation that has higher ethanol content, I have noticed that it detonates at WOT now.
The car is a '99 that's bone stock other than a Blackwing intake and a Corsa exhaust.
I filled up with Chevron and haven't driven the car in two weeks. Maybe it's a bad tank of gas? Also, the previous owner installed some NGK plugs not that long ago. I pulled one of them to diagnose another issue unrelated to this one, and it looked fine. The plug wires look new too. With the recent switch in gas formulation that has higher ethanol content, I have noticed that it detonates at WOT now.
The car is a '99 that's bone stock other than a Blackwing intake and a Corsa exhaust.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
Never know - this TSB might apply. It's for '99 MY C5's.
1999: Service Bulletin: Hesitation, Sag, Stumble and/or Backfire on Acceleration (Reprogram PCM) Subject: Hesitation, Sag, Stumble and/or Backfire on Acceleration
Source: Chevrolet Service Bulletin
Number: 99-06-04-030
Models: 1999 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1)
Condition:
Some customers may comment on a hesitation, sag, stumble and/or backfire on acceleration during cool summer days/evenings with ambient temperature below 10°C (50°F).
Cause:
Condition may be due to lean calibration with Low Reed Vapor Pressure Fuels (summer grade premium fuel) at lower ambient temperatures, below 10°C (50°F).
Correction:
Reprogram the PCM with a new service calibration.
Parts Information
Previous Calibration P/N
New Calibration P/N
16263856
16263683
16263857
16263701
16263858
16263709
16263859
16263710
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline on the 1999 Disc 10 CD ROM or the TIS 2000 Disc 12 CD ROM.
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.
© Copyright General Motors Corporation. All Rights Reserved.
1999: Service Bulletin: Hesitation, Sag, Stumble and/or Backfire on Acceleration (Reprogram PCM) Subject: Hesitation, Sag, Stumble and/or Backfire on Acceleration
Source: Chevrolet Service Bulletin
Number: 99-06-04-030
Models: 1999 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1)
Condition:
Some customers may comment on a hesitation, sag, stumble and/or backfire on acceleration during cool summer days/evenings with ambient temperature below 10°C (50°F).
Cause:
Condition may be due to lean calibration with Low Reed Vapor Pressure Fuels (summer grade premium fuel) at lower ambient temperatures, below 10°C (50°F).
Correction:
Reprogram the PCM with a new service calibration.
Parts Information
Previous Calibration P/N
New Calibration P/N
16263856
16263683
16263857
16263701
16263858
16263709
16263859
16263710
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline on the 1999 Disc 10 CD ROM or the TIS 2000 Disc 12 CD ROM.
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.
© Copyright General Motors Corporation. All Rights Reserved.
Thread Starter
Instructor
Joined: Dec 2005
Posts: 100
Likes: 0
From: Austin, TX
Originally Posted by Patches
Never know - this TSB might apply. It's for '99 MY C5's.
1999: Service Bulletin: Hesitation, Sag, Stumble and/or Backfire on Acceleration (Reprogram PCM) Subject: Hesitation, Sag, Stumble and/or Backfire on Acceleration
Source: Chevrolet Service Bulletin
Number: 99-06-04-030
Models: 1999 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1)
Condition:
Some customers may comment on a hesitation, sag, stumble and/or backfire on acceleration during cool summer days/evenings with ambient temperature below 10°C (50°F).
Cause:
Condition may be due to lean calibration with Low Reed Vapor Pressure Fuels (summer grade premium fuel) at lower ambient temperatures, below 10°C (50°F).
Correction:
Reprogram the PCM with a new service calibration.
Parts Information
Previous Calibration P/N
New Calibration P/N
16263856
16263683
16263857
16263701
16263858
16263709
16263859
16263710
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline on the 1999 Disc 10 CD ROM or the TIS 2000 Disc 12 CD ROM.
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.
© Copyright General Motors Corporation. All Rights Reserved.
1999: Service Bulletin: Hesitation, Sag, Stumble and/or Backfire on Acceleration (Reprogram PCM) Subject: Hesitation, Sag, Stumble and/or Backfire on Acceleration
Source: Chevrolet Service Bulletin
Number: 99-06-04-030
Models: 1999 Chevrolet Corvette with 5.7 L Engine (VIN G -- RPO LS1)
Condition:
Some customers may comment on a hesitation, sag, stumble and/or backfire on acceleration during cool summer days/evenings with ambient temperature below 10°C (50°F).
Cause:
Condition may be due to lean calibration with Low Reed Vapor Pressure Fuels (summer grade premium fuel) at lower ambient temperatures, below 10°C (50°F).
Correction:
Reprogram the PCM with a new service calibration.
Parts Information
Previous Calibration P/N
New Calibration P/N
16263856
16263683
16263857
16263701
16263858
16263709
16263859
16263710
The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline on the 1999 Disc 10 CD ROM or the TIS 2000 Disc 12 CD ROM.
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.
© Copyright General Motors Corporation. All Rights Reserved.
Le Mans Master
Joined: Oct 2002
Posts: 6,855
Likes: 2
From: Grovetown GA
Originally Posted by FRC Shopper
At slow speeds under load, I get a strange hesitation. For example, if I'm in 3rd gear at 20 mph and give half throttle, the car accelerates very slowly. The weird thing is, if I let off the gas, then get back on it, the car accelerates as it should. I know P0300 is a misfire code, but I can't actually feel a noticeable misfire. Just hesitation.
I filled up with Chevron and haven't driven the car in two weeks. Maybe it's a bad tank of gas? Also, the previous owner installed some NGK plugs not that long ago. I pulled one of them to diagnose another issue unrelated to this one, and it looked fine. The plug wires look new too. With the recent switch in gas formulation that has higher ethanol content, I have noticed that it detonates at WOT now.
The car is a '99 that's bone stock other than a Blackwing intake and a Corsa exhaust.
I filled up with Chevron and haven't driven the car in two weeks. Maybe it's a bad tank of gas? Also, the previous owner installed some NGK plugs not that long ago. I pulled one of them to diagnose another issue unrelated to this one, and it looked fine. The plug wires look new too. With the recent switch in gas formulation that has higher ethanol content, I have noticed that it detonates at WOT now.
The car is a '99 that's bone stock other than a Blackwing intake and a Corsa exhaust.
My 99 FRC developed a "stumble" yesterday - apparently all of a sudden. It stumbles when under a load at low rpm (6th gear at 70 MPH) and gets an erratic idle when it gets warm. It is throwing no misfire codes but it sure feels like it is misfiring...
Any clues?
Did you get your problem fixed?
thanks!
