* Fuel Delivery Issues:
* Clogged Fuel Filter: This is a very common and relatively inexpensive fix. A clogged filter restricts fuel flow, especially under increased demand during acceleration.
* Weak Fuel Pump: The pump might be able to supply enough fuel for cruising but struggles to keep up when more fuel is needed for acceleration. This is more likely if the hesitation is worse when the tank is low.
* Clogged Fuel Injectors: Clogged injectors can't deliver the proper amount of fuel to the cylinders, leading to hesitation. This is a more involved fix, potentially requiring cleaning or replacement.
* Low Fuel Pressure: A problem in the fuel pressure regulator could cause insufficient pressure, leading to similar symptoms.
* Ignition System Problems:
* Worn Spark Plug Wires: Cracked or worn wires can cause misfires, leading to hesitation. These are relatively easy to inspect and replace.
* Failing Ignition Coil: A weak or failing coil may not provide enough spark to ignite the fuel-air mixture consistently, especially under load.
* Distributor Cap and Rotor (if applicable): These components, if present in your specific Roadmaster's engine, can wear out, causing poor ignition. Cracks or corrosion can disrupt the spark.
* Mass Airflow Sensor (MAF) or Throttle Position Sensor (TPS): These sensors provide crucial information to the engine's computer about air intake and throttle position. A faulty sensor can cause incorrect fuel-air mixture calculations, leading to hesitation. These are more likely to cause problems across the rev range, but can still manifest primarily during acceleration.
* Other Possibilities:
* Vacuum Leaks: A leak in the intake manifold or vacuum lines can disrupt the proper air-fuel mixture.
* Transmission Issues (less likely): While less probable given the description, a problem within the transmission's torque converter could theoretically cause hesitation, but usually manifests in other ways as well.
Troubleshooting Steps:
1. Check the basics: Start with the easiest and cheapest checks: fuel filter, spark plug wires (look for cracks or fraying).
2. Check the fuel pressure: This requires a fuel pressure gauge and may necessitate a visit to a mechanic.
3. Scan the codes: Use an OBD-II scanner to retrieve any diagnostic trouble codes (DTCs) stored in the engine's computer. This can help pinpoint the problem. A 1993 model might require a scanner specific to older OBD systems.
4. Inspect the ignition components: Visually inspect the distributor cap, rotor (if applicable), and ignition coil for signs of wear or damage.
5. Check the MAF and TPS sensors: This often requires a multimeter or professional diagnostic tools.
Because the problem only happens during acceleration, issues related to *consistent* fuel delivery or ignition (like a completely bad fuel pump) are less likely. The symptoms strongly suggest an intermittent problem related to the system's ability to *increase* fuel and/or spark delivery under load. Start with the easier checks (fuel filter, spark plug wires) before moving to more involved diagnostics. If you're not comfortable working on your car yourself, a qualified mechanic should be able to diagnose the issue quickly.
