* Oil Pump Issues: The most likely culprit is a failing oil pump. At idle, the pump may not generate sufficient pressure to trigger the sensor. When you accelerate, the engine speed increases, forcing the pump to work harder and temporarily overcome the deficiency, resulting in sufficient pressure to turn the light off. A worn or failing pump is a serious issue and needs immediate attention.
* Low Oil Level: While less likely given the description, very low oil levels can also cause this. The oil may be insufficient to maintain pressure at low engine speeds.
* Clogged Oil Filter/Pick-up: A severely clogged oil filter or a blocked oil pick-up in the oil pan will restrict oil flow, leading to low pressure at idle.
* Worn Engine Bearings: Worn bearings within the engine create larger clearances, requiring more oil to maintain pressure. This could manifest as the described symptom. This is a serious mechanical problem.
* Oil Pressure Sensor: Although less probable, a faulty oil pressure sensor could be giving a false low-pressure reading at idle. However, this is less likely because it would likely remain on regardless of engine speed.
What you should do IMMEDIATELY:
1. Do NOT continue driving. Driving with low oil pressure can cause catastrophic engine damage, leading to a very expensive repair or even a need for engine replacement.
2. Check your oil level. Use the dipstick. If it's low, add oil *carefully* and check again. However, low oil doesn't explain the problem completely if the light only comes on at idle.
3. Have the car towed to a qualified mechanic. They can diagnose the exact cause of the low oil pressure and perform the necessary repairs. Ignoring this problem will likely result in significant engine damage.
The behavior of the oil light is a clear warning sign of a potential major problem. Do not delay seeking professional help.
