I have a 1994 toyota 4x4 v6 that has recently been rebuilt ~2000 miles ago. it really feels gutless to me. its like it has more to give but cant. it acts similar to a mass flow sensor problem I have had in the past with another vehicle. the code is 71. I think this is an egr system problem. will this cause power loss and bad gas mileage? Im getting ~ 16 mi/gal. also is it normal to hear mild ticking from the engine?

Thanks. would this cause significant power loss and or poor gas mileage? Thanks. would this cause significant power loss and or poor gas mileage?

With out a doubt, this would cause poor fuel mileage and loss of power. The EGR system is desgined to recirculate exhaust back into the intake system, and when this is done, it cools the combustion chamber. With the code you received, this is the best place to start and I would not be surprised if the passages are clogged. With out a doubt, this would cause poor fuel mileage and loss of power. The EGR system is desgined to recirculate exhaust back into the intake system, and when this is done, it cools the combustion chamber. With the code you received, this is the best place to start and I would not be surprised if the passages are clogged.

Thanks again. Ill try it. Thanks again. Ill try it.

Comment back with the results. Comment back with the results.

I tried the vacuum test. I did not have the hand held, but I had some extra tubing, and I drew a vacuum with my mouth and the truck did not die out but it got really close. does this mean it is not stuck or clogged? I tried the vacuum test. I did not have the hand held, but I had some extra tubing, and I drew a vacuum with my mouth and the truck did not die out but it got really close. does this mean it is not stuck or clogged?

I'm not sure you can apply enough Vac to this unit without a pump, the engine should stall. This will verify the EGR diaphram is working, but you may still have a clog. I'm not sure you can apply enough Vac to this unit without a pump, the engine should stall. This will verify the EGR diaphram is working, but you may still have a clog.

Diagnosis; 60 seconds after start of EGR operation, EGR gas temp is less than 158 degress F and the following also occur.

1. Engine coolant temp 127 F or more.

2.Engine speed; 1,200 RPM or more.

3. Intake air temp 32 degrees or more.

These are the values programmed to the PCM and conditions must me met. If not, the Code will be stored.Possible causes are:



EGR valve

EGR hose

EGR gas temp circuit

EGR gas temp sensor

VSV for EGR

VSV circuit for EGR

PCM (Computer) this is not likely but I do mention it. Diagnosis; 60 seconds after start of EGR operation, EGR gas temp is less than 158 degress F and the following also occur.
1. Engine coolant temp 127 F or more.
2.Engine speed; 1,200 RPM or more.
3. Intake air temp 32 degrees or more.
These are the values programmed to the PCM and conditions must me met. If not, the Code will be stored.Possible causes are:

EGR valve
EGR hose
EGR gas temp circuit
EGR gas temp sensor
VSV for EGR
VSV circuit for EGR
PCM (Computer) this is not likely but I do mention it.

I pull a stronger vacuum. I compared what the truck was pulling at idle, at 2000rpm and at 3500rpm with what i was pulling, and there was an obvious difference. I will remove it and clean it tomorrow though.

I pull a stronger vacuum. I compared what the truck was pulling at idle, at 2000rpm and at 3500rpm with what i was pulling, and there was an obvious difference. I will remove it and clean it tomorrow though.

sorry, one more question. what is the best way to clean it? do I need to soak it or something? sorry, one more question. what is the best way to clean it? do I need to soak it or something?

You can use a small screw driver to chisel away the carbon and cover any areas that you do n ot want carbon to get into. I also use a wet/dry vacuum to assist in pulling any loose material. You can use a small screw driver to chisel away the carbon and cover any areas that you do n ot want carbon to get into. I also use a wet/dry vacuum to assist in pulling any loose material.

ok, so I decided to dive in this evening. the valve does not seem to be clogged. I removed it and bench tested it and when I applied vacuum there was clear flow thru the valve. a.lso it was visibly clean, but I attempted to scrape what I could. I reinstalled and found an auxilary vacuum port on the top of the engine and retried the stall out test using the port and it did die out. then I checked the vacuum to the valve, which I guess i should have checked first, and there is no vacuum at idle which I kinda expected, but there is also no vacuum when steadily reved. is there a circuit that calls for vacuum at a certain rpm or something? from what I can see there doues not seem to be any kinks in the line. what next? ok, so I decided to dive in this evening. the valve does not seem to be clogged. I removed it and bench tested it and when I applied vacuum there was clear flow thru the valve. a.lso it was visibly clean, but I attempted to scrape what I could. I reinstalled and found an auxilary vacuum port on the top of the engine and retried the stall out test using the port and it did die out. then I checked the vacuum to the valve, which I guess i should have checked first, and there is no vacuum at idle which I kinda expected, but there is also no vacuum when steadily reved. is there a circuit that calls for vacuum at a certain rpm or something? from what I can see there doues not seem to be any kinks in the line. what next?

1. Remove the EGR vacuum modulator cap and filter.


2. Check the filter for damage or contamination.


3. With compressed air, clean the filter.


4. Reinstall the filter and cap. Install the filter with the coarser surface facing the atmospheric side (outwards).


5. Using a 3-way connector, attach a vacuum gauge to the hose between the EGR valve and the EGR vacuum modulator.


6. Start the engine and check that the engine starts and runs at idle.

1. Check that the vacuum gauge indicates zero at 3000 rpm.


2. Check that the EGR pipe is not hot.


3. Remove the 3-way connector with the vacuum hose.


4. Connect the vacuum hose from port Q of the EGR modulator to the EGR valve.


5. Plug the hose from the VSV to the EGR.


6. Remove the vacuum gauge, then reconnect the vacuum hoses to their proper locations.


7. Apply vacuum directly to the EGR valve with the engine at idle.

1. Check that the engine now idles rough or stalls.



2. Reconnect the vacuum hoses to their proper locations.

1. Check the filter in the EGR modulator for contamination and clean using compressed air.



2. Using a 3-way connector, connect a vacuum gauge inline between the valve and vacuum pipe.

1. Accelerate the engine to 2500 rpm and verify that the vacuum gauge reads 0 in. Hg.



2. Check that the EGR pipe is not hot.

1. Check that the vacuum gauge reads low vacuum at 2500 rpm.



2. Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the intake manifold.



3. Check that the vacuum reading is high at 2500 rpm. As large amounts of vacuum enters the engine, the engine idle quality may be adversely affected.



4. Remove the vacuum gauge and reconnect the vacuum hoses in their original locations.



5. Apply vacuum directly to the EGR valve with the engine at idle.



6. If the EGR valve is operating properly, the engine should misfire, run rough and possibly stall. Reconnect the vacuum hoses in their proper locations.

1. Check the filter in the EGR modulator for contamination and clean using compressed air.



2. Using a 3-way connector, connect a vacuum gauge inline between the valve and vacuum pipe.



3. Check that the engine starts and idles smoothly.

1. Accelerate the engine to 3500 rpm and verify that the vacuum gauge reads 0.

1. Check that the vacuum gauge reads low vacuum at 3500 rpm.



2. Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the intake manifold.



3. Check that the vacuum reading is high at 3000 rpm. As large amounts of vacuum enters the engine, the engine idle quality may be adversely affected.



4. Remove the vacuum gauge and reconnect the vacuum hoses in their original locations.



5. Apply vacuum directly to the EGR valve with the engine at idle. If the EGR valve is operating properly, the engine should run rough or possibly stall.



6. Reconnect the vacuum hoses in their proper locations.

1. Remove the EGR vacuum modulator cap and filter.



2. Check the filter for damage or contamination.



3. With compressed air, clean the filter.



4. Reinstall the filter and cap. Install the filter with the coarser surface facing the atmospheric side (outwards).



5. Using a 3-way connector, attach a vacuum gauge to the hose between the EGR valve and the VSV.



6. Start the engine and check that the engine starts and runs at idle.



7. Using the SST 09843-18020 or an equivalent jumper wire, connect terminals TE1 and E1 of the DLC1 under the hood.

1. Remove the EGR vacuum modulator cap and filter.
2. Check the filter for damage or contamination.
3. With compressed air, clean the filter.
4. Reinstall the filter and cap. Install the filter with the coarser surface facing the atmospheric side (outwards).
5. Using a 3-way connector, attach a vacuum gauge to the hose between the EGR valve and the EGR vacuum modulator.
6. Start the engine and check that the engine starts and runs at idle.

The engine coolant temperature should be below 122°F (20°C).

1. Check that the vacuum gauge indicates zero at 3000 rpm.
2. Check that the EGR pipe is not hot.
3. Remove the 3-way connector with the vacuum hose.
4. Connect the vacuum hose from port Q of the EGR modulator to the EGR valve.
5. Plug the hose from the VSV to the EGR.
6. Remove the vacuum gauge, then reconnect the vacuum hoses to their proper locations.
7. Apply vacuum directly to the EGR valve with the engine at idle.

1. Check that the engine now idles rough or stalls.
2. Reconnect the vacuum hoses to their proper locations.

1FZ-FE Engines

1. Check the filter in the EGR modulator for contamination and clean using compressed air.
2. Using a 3-way connector, connect a vacuum gauge inline between the valve and vacuum pipe.

Check that the engine starts and idles smoothly.
For accurate system testing, the coolant temperature should be below 117°F (47°C).

1. Accelerate the engine to 2500 rpm and verify that the vacuum gauge reads 0 in. Hg.
2. Check that the EGR pipe is not hot.

For accurate test results, the engine coolant temperature must now be above 127°F (53°C)

1. Check that the vacuum gauge reads low vacuum at 2500 rpm.
2. Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the intake manifold.
3. Check that the vacuum reading is high at 2500 rpm. As large amounts of vacuum enters the engine, the engine idle quality may be adversely affected.
4. Remove the vacuum gauge and reconnect the vacuum hoses in their original locations.
5. Apply vacuum directly to the EGR valve with the engine at idle.
6. If the EGR valve is operating properly, the engine should misfire, run rough and possibly stall. Reconnect the vacuum hoses in their proper locations.

22R-E and 3VZ-E Engines

1. Check the filter in the EGR modulator for contamination and clean using compressed air.
2. Using a 3-way connector, connect a vacuum gauge inline between the valve and vacuum pipe.
3. Check that the engine starts and idles smoothly.

For accurate system testing, the coolant temperature should be below 118°F (48°C) on 3VZ-E engines or below 93°F (34°C) on 22R-E engines.

1. Accelerate the engine to 3500 rpm and verify that the vacuum gauge reads 0.

For accurate test results, the engine coolant temperature must be above 126°F (52°C) on 3VZ-E engines or above 104°F (40°C) on 22R-E engines.

1. Check that the vacuum gauge reads low vacuum at 3500 rpm.
2. Disconnect the vacuum hose from port R of the EGR vacuum modulator and connect port R directly to the intake manifold.
3. Check that the vacuum reading is high at 3000 rpm. As large amounts of vacuum enters the engine, the engine idle quality may be adversely affected.
4. Remove the vacuum gauge and reconnect the vacuum hoses in their original locations.
5. Apply vacuum directly to the EGR valve with the engine at idle. If the EGR valve is operating properly, the engine should run rough or possibly stall.
6. Reconnect the vacuum hoses in their proper locations.

5VZ-FE Engine

1. Remove the EGR vacuum modulator cap and filter.
2. Check the filter for damage or contamination.
3. With compressed air, clean the filter.
4. Reinstall the filter and cap. Install the filter with the coarser surface facing the atmospheric side (outwards).
5. Using a 3-way connector, attach a vacuum gauge to the hose between the EGR valve and the VSV.
6. Start the engine and check that the engine starts and runs at idle.
7. Using the SST 09843-18020 or an equivalent jumper wire, connect terminals TE1 and E1 of the DLC1 under the hood.