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ACDelco GM Original Equipment Ignition Distributor Cap D303A

GM Original Equipment


An ACDelco GM Original Equipment Distributor Cap is a GM-recommended replacement for your vehicle’s original component. It covers the top of the distributor and provides half of the rotary switch (distributor rotor). This original equipment distributor cap has been manufactured to fit your GM vehicle, providing the same performance, durability, and service life you expect from General Motors.

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Pricing: $29.34


Ignition Distributor Cap

Get the GM quality you know and trust with ACDelco GM Original Equipment Ignition System and Switch products. Stay with the brand of parts your General Motors vehicle came with and get peace of mind that the fit, form, and function is up to the high standards and specifications of General Motors. ACDelco GM Original Equipment Ignition System and Switch products are engineered for all models of GM vehicles on the road today.

Warranty: 24 Month / Unlimited Mile Limited Warranty on parts sold on or after 04/01/18. (Parts Only) Please see for more details.

Features & Benefits:

  • Have metal inserts designed to provide the best possible fit to ensure maximum conductivity between the distributor towers and spark plug wires
  • Easy-to-read locator keys on caps make proper installation simple
  • Equipped with a full anti-arc barrier to reduce the possibility of secondary voltage arcs that can cause an engine to misfire
  • GM-recommended replacement part for your GM vehicle's original factory component
  • Offering the quality, reliability, and durability of GM OE
  • Manufactured to GM OE specification for fit, form, and function


Q: Is there a problem when my 'Service Engine Soon' light appears?
A: When your 'Service Engine Soon' light illuminates, that is an indication that there is a potential issue with the drivability, electronics, or emissions of your engine.

Q: While investigating what triggered the 'Service Engine Soon' light, do you recommend any additional services?
A: Preventative maintenance should be referenced in your owner's manual, and, while repairing or having your 'Service Engine Soon' light repaired, if your vehicle is due for maintenance, yes. As described in your owner's manual, this maintenance will help prevent future issues.

Q: If I don't investigate the problem, will the light turn off by itself?
A: Possibly. Sometimes, the triggering device will reset itself thus turning off the 'Service Engine Soon' light until that device/sensor is tested by the vehicles on board computer again. If it fails the test again when tested, the 'Service Engine Soon' light will illuminate once again. Some devices/sensors when tested and failed will illuminate the 'Service Engine Soon' and it will not go out until correct service work is performed.

Q: If I ignore the light, will there be consequences?
A: General Motors has designed the vehicle to inform its driver if there is an issue with certain devices/sensors that effect the drivability/emissions. If this is ignored, there is a possibility that the drivability will suffer, fuel economy will be decreased, or the emissions being emitted will be increased. Do not ignore the 'Service Engine Soon' light.

Q: Is it possible for my vehicle to pass an emissions test if the 'Service Engine Soon' light is on?
A: No. When state and local officials perform certified emission tests, one of the first steps in the process is to inspect for a 'Service Engine Soon'. If it is on, it will automatically fail the test.

Q: Does the 'Service Engine Soon' light tell me when my vehicle needs a tune-up?
A: No. The 'Service Engine Soon' is related to engine emissions and drivability conditions. Please refer to your owner's manual maintenance schedule for information pertaining to tune up time intervals.

Maintenance & Troubleshooting

Signs of Wear & Troubleshooting

  • Due to a broken or sheared drive gear, broken or sheared shaft, worn or broken rotor, worn or cracked distributor cap, loose or disconnected low or high voltage wires, these problems may occur:
    • Engine will not start or run
    • Engine misfires/backfires
    • Abnormal noise
    • Excessive tailpipe emissions
    • Reduced fuel economy
    • Service Engine Soon light illuminates

Good Maintenance Practices

  • Having your service technician regularly inspect your ignition system can help you stay away from conditions that may result in poor performance or reduced fuel economy.

California Proposition 65

California Prop 65WARNING: Cancer & Reproductive Harm -


  • D303A
  • D303A
  • ACDelco
  • New


Shipping Information

  • Item Requires Shipping
  • 0.5 lbs.
  • W5.7000” x H4.2000” x L6.7000”
  • Free Shipping* On Orders Over $99!

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