High fuel consumption

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When you replaced the pump, was the regulator inspected? Have you checked fuel pressure to see if it is too high?

I attached two pictures. The first shows where the regulator is located in relationship with the pump. The second picture is what the regulator looks like.

I would start by confirming the fuel pressure is within the manufacturer's specs. If it is too high, it can cause a rich fuel mixture and use more fuel.

Here is a link showing how fuel pressure is checked:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

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Here are the directions specific to your vehicle for testing. The attached pics correlate with the directions and the manufacturer's specs are in the directions.

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2003 Toyota Corolla CE Sedan L4-1.8L (1ZZ-FE)
Component Tests and General Diagnostics
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Testing and Inspection Component Tests and General Diagnostics
COMPONENT TESTS AND GENERAL DIAGNOSTICS

pic 3

CHECK FUEL PRESSURE
a. Prepare for inspection.
1. Purchase a new fuel tube, and take out the fuel tube connector from its tube.

HINT: Part No. 23901-OD010

b. Work for prevent gasoline from spilling out.
c. Disconnect the EFI fuel pipe clamp.
d. Disconnect the fuel tube from the fuel main tube.

pic 4

e. Install SST (pressure gauge) as shown in the illustration by using the SST and fuel tube connector.

SST 09268-41047 (90467-13001, 95336-08070), 09268-45014 (09268-41200, 09268-41220, 09268-41250, 90467-13001)

f. Wipe off any splattered gasoline.
g. Start the engine.
h. Measure the fuel pressure at idle.

Fuel pressure: .................... 304 - 343 kPa (3.1 - 3.5 kgf.sq.cm, 44 - 50 psi)

i. Stop the engine.
j. Check that the fuel pressure remains as specified for 5 minutes after the engine has stopped.

Fuel pressure: .................... 147 kPa (1.5 kgf.sq.cm, 21 psi) or more

If pressure is not as specified, check the fuel pump, pressure regulator and/or injectors.

k. After checking fuel pressure, disconnect the negative (-) terminal cable from the battery and carefully, remove the SST and fuel tube connector to prevent gasoline from the splashing.

l. Reconnect the fuel tube to fuel main tube.
m. Install the EFI fuel pipe clamp.
n. Check fuel leak.

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Let me know if this helps and what you find. If you have other questions, let me know.

Take care,
Joe