1. Engine Knock:
- It could be a result of piston slap, which is when the piston moves within the cylinder and creates a knocking noise. This can occur due to excessive wear or insufficient oil pressure.
2. Faulty Timing Chain or Belt:
- A worn or loose timing chain or belt can cause a thumping sound as it slips over the sprockets.
3. Vacuum Leak:
- A leak in the vacuum system can cause various issues, including a thumping noise and a check engine light. Check for any loose or cracked vacuum hoses.
4. Fuel Injector Issue:
- A malfunctioning fuel injector can create a thumping noise and cause the engine to run rough.
5. Transmission Problems:
- If the thumping noise is coming from the transmission area, it could indicate issues such as worn gears or low transmission fluid.
6. Faulty Engine Mount:
- A faulty or loose engine mount can cause the engine to vibrate excessively and produce a thumping noise.
It's important to address this issue as soon as possible to prevent further damage to your minivan. If you're not comfortable diagnosing and fixing the problem yourself, I highly recommend taking your vehicle to a qualified mechanic for a professional diagnosis and repair.
