However, a significant exhaust leak *could* indirectly contribute to these problems in a few ways:
* Incorrect Air/Fuel Mixture: A large hole in the muffler could allow unmetered air to enter the exhaust system, potentially affecting the air/fuel mixture read by the oxygen sensor. This could lead to a lean condition, causing the engine to run faster or less efficiently. This is more likely if the leak is before the catalytic converter.
* Backpressure Issues (Less Likely): While exhaust backpressure is important, a hole in the muffler generally *reduces* backpressure, not increases it. Increased backpressure would typically cause a loss of power, not an increase in RPM. A very large leak *might* have a strange effect by disrupting the normal exhaust flow, but it's not the primary cause.
More Likely Culprits:
The symptoms you describe (higher RPM in park/neutral and excessive pulling) point towards other issues, such as:
* Throttle Position Sensor (TPS): A faulty TPS can cause inaccurate readings of the throttle position, leading to higher idle speeds and poor engine response.
* Idle Air Control (IAC) Valve: This valve regulates air flow at idle. A malfunctioning IAC valve can cause high idle speeds.
* Vacuum Leaks: Leaks in the vacuum system can affect various engine components and lead to erratic idle and performance issues.
* Transmission Problems: Excessive pulling could indicate issues with the transmission itself, such as a slipping clutch or other internal problems (especially if it's only under load).
In short: While a very large exhaust leak *might* contribute to the problems marginally, it's highly unlikely to be the primary cause. You should focus on investigating the TPS, IAC valve, vacuum system, and the transmission as more likely culprits. A mechanic can diagnose the issue properly.
