What you're likely experiencing are symptoms related to *something else* that's manifesting as perceived timing problems, or a problem with the communication between the engine and transmission control systems. Here are some possibilities:
* Torque Converter Issues: A malfunctioning torque converter (the fluid coupling between the engine and transmission) can cause slippage, leading to a feeling of delayed or erratic acceleration. This might feel like a timing problem because the engine revs but the car doesn't accelerate proportionally.
* Transmission Problems: A worn transmission, slipping clutch packs, or low transmission fluid can also cause similar symptoms. The transmission might not be engaging properly, creating a disconnect between engine speed and vehicle speed.
* Sensors/Solenoids: Various sensors (crankshaft position sensor, camshaft position sensor, throttle position sensor, etc.) and solenoids within the engine or transmission control system could be failing. Incorrect signals from these components can lead to improper shifting, poor acceleration, or even stalling, all mimicking a timing issue.
* Wiring Harness Problems: A damaged or corroded wiring harness connecting the engine and transmission control units could be causing intermittent faults.
* Computer Issues (PCM): A failing Powertrain Control Module (PCM) – the computer that manages both the engine and transmission – is a possibility. A faulty PCM can lead to numerous drivability problems, including irregular shifting and acceleration.
To diagnose the problem, consider these steps:
1. Check Transmission Fluid: Low or dirty transmission fluid is a common cause of transmission problems. Check the level and condition of the fluid. If it's low, have it topped off with the correct type of fluid. If it's dark or smells burnt, a transmission flush or repair might be needed.
2. Have the Codes Scanned: Use an OBD-II scanner to check for diagnostic trouble codes (DTCs). These codes will pinpoint potential problems within the engine or transmission control systems.
3. Inspect the Torque Converter: This is more difficult and usually requires a mechanic. A faulty torque converter can exhibit symptoms similar to a timing issue.
4. Professional Diagnosis: Given the complexity of potential issues, a qualified mechanic specializing in older vehicles is the best option. They have the tools and expertise to diagnose the problem accurately and safely.
In short: Focus your investigation on the transmission and its related systems, rather than the engine's internal timing mechanism. The symptoms you describe point more strongly towards a drivetrain problem than a timing chain or belt issue.
