Check engine light

  • 6 CYL
  • 2WD
  • 240,000 MILES
All of a sudden driving home from work I lost second and third gear, starts to vibrate like crazy. No check engine light. I changed out the transmission solenoids and cleaned out the sludge in the pan. Drove fine. The check engine light comes on and it says running lean probably a clogged fuel filter. Changed fuel filter, light goes off and came back on. Running rough but not in drivable. What is the problem?
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Wednesday, March 18th, 2020 AT 7:06 PM

1 Reply


What codes were found? Did replacement of the solenoids make a difference with shifting? Also, as far as a lean mixture, it could be related to low fuel pressure, a vacuum leak and so on. However, usually it's a vacuum leak. If possible, let me know what code was found to indicate a lean mixture and if you have a live data scanner, let me know the short term fuel trims.

If you don't have a scanner, here is a link that explains how to locate and repair an engine vacuum leak:

Also, here is a link that shows in general how to check fuel pressure:


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

2000 Toyota Truck 4 Runner 2WD L4-2.7L (3RZ-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



pic 1

a. Connect the TOYOTA hand-held tester to the DLC3.
b. Turn the ignition switch ON and TOYOTA hand-held tester main switch ON.

NOTE: Do not start the engine.

c. Select the active test mode on the TOYOTA hand-held tester.
d. Please refer to the TOYOTA hand-held tester operator's manual for further details.

e. If you have no TOYOTA hand-held tester, connect the positive (+) and negative (-) leads from the battery to the fuel pump connector.

pic 2

f. Check that there is pressure in the inlet hose from the fuel filter.

HINT: At this time, you will hear fuel return noise.
If there is no pressure, check these parts:
- M-Fuse (AM2 30A)
- Fuses (EFI 15A, IGN 7.5A)
- EFI main relay
- Fuel pump
- Wiring connections

g. Turn the ignition switch to LOCK.
h. Remove the TOYOTA hand-held tester.

pic 3

a. Check that the battery positive voltage is above 12 volts.
b. Disconnect the negative (-) terminal cable from the battery.
c. Remove the union bolt and 2 gaskets, and disconnect the fuel inlet pipe from the delivery pipe.

- Put a suitable container or shop rag under the delivery pipe.
- Slowly loosen the union bolt.

pic 4

d. Install the fuel inlet pipe and SST (pressure gauge) to the delivery pipe with the 3 gaskets and SST (union bolt).
SST 09268-45014

Torque: 29 Nm (300, 22

e. Wipe off any splattered gasoline.
f. Connect the TOYOTA hand-held tester to the DLC3. (See step 1.)
g. Reconnect the negative (-) terminal cable to the battery.
h. Turn the ignition switch ON.
i. Measure the fuel pressure.

Fuel pressure: 265 - 304 kPa (2.7 - 3.1 kg/, 38 - 44 psi)

If pressure is high, replace the fuel pressure regulator.
If pressure is low, check these parts:
- Fuel hoses and connections
- Fuel pump
- Fuel filter
- Fuel pressure regulator
- Injectors

j. Disconnect the TOYOTA hand-held tester from the DLC3.
k. Start the engine.
l. Measure the fuel pressure at idle.

Fuel pressure: 206 - 255 kPa (2.1 - 2.6 kg/, 31 - 37 psi)

If pressure is not as specified, check the vacuum sensing hose and fuel pressure regulator.

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

Fuel pressure: 147 kPa (1.5 kg/, 21 psi) or more If pressure is not as specified, check the fuel pump, pressure regulator and/or injector.

o. After checking fuel pressure, disconnect the negative (-) terminal cable from the battery and carefully remove the SST to prevent gasoline from splashing.
SST 09268-45014
p. Reconnect the fuel inlet pipe to the delivery pipe with 2 new gaskets and the union bolt.

Torque: 29 Nm (300, 22

q. Reconnect the negative (-) terminal cable to the battery.
r. Check for fuel leakage.


Let me know if this helps and what you find. Also, if you could provide the info I requested, it may help me diagnose possible issues.

Take care,
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Wednesday, March 18th, 2020 AT 7:31 PM

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