* Weak Fuel Pump: This is the most frequent cause. The pump may not be able to keep up with the increased fuel demand during acceleration. It could be failing due to age, wear, or simply insufficient power to push enough fuel under higher pressure.
* Clogged Fuel Filter: A dirty fuel filter restricts fuel flow, leading to a pressure drop under load. This is a relatively inexpensive and easy fix.
* Leaking Fuel Pressure Regulator: The regulator controls fuel pressure. If it's leaking internally or externally, it can't maintain the correct pressure, especially when the engine demands more fuel.
* Clogged Fuel Injectors: While less likely to cause a *sudden* pressure drop, heavily clogged injectors can create a restriction, making the pump work harder and potentially leading to lower pressure under heavy acceleration. This is more likely to manifest as poor performance rather than a direct pressure drop reading.
* Fuel Pump Relay: A faulty relay won't supply sufficient power to the fuel pump, resulting in weak or intermittent pressure.
* Problems in the Fuel Lines: A kink, collapse, or restriction in the fuel lines can restrict flow.
* Low Fuel Level: While not directly a pressure issue, a very low fuel level can sometimes impact the pump's ability to draw fuel effectively, causing low pressure.
Troubleshooting Steps:
1. Check the Fuel Filter: This is the easiest and cheapest first step. Replace it if it's dirty or old.
2. Measure Fuel Pressure: Use a fuel pressure gauge to accurately measure the pressure at idle and during acceleration. Compare your readings to the factory specifications for your TPI system (easily found online). This will confirm if you actually have a pressure problem.
3. Inspect Fuel Lines: Visually inspect the fuel lines for any kinks, cracks, or damage.
4. Test the Fuel Pump: This can involve several methods: listening for the pump's prime sound when the ignition is turned on, measuring pump voltage, or even directly testing the pump's output (this often requires some specialized tools).
5. Check the Fuel Pressure Regulator: Inspect it for leaks and ensure it's functioning correctly. Testing may require a pressure gauge and some additional equipment.
6. Inspect the Fuel Pump Relay: Try swapping the relay with another (of the same type) to rule out a relay malfunction.
Important Note: Working with fuel systems involves flammable liquids and potential fire hazards. If you're not comfortable performing these checks yourself, take your car to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and safely.
