Over the years I have had various hesitation issues, no codes. I would cycle? the electric connection to the EGR and the car would run fine for a few months. Recently The car threw many different codes; P0300-P0306, P0171. Changed the Air/fuel sensor, O2 sensor, PCV, Spark plugs, Rear (135 manifold) catalytic converter, EGR assy. Now my issue is; idle and full throttle really runs fine. Light throttle I get mis-fires/hesitation. If I remove the EGR vacuum line it runs much better (still feel light hesitation but not all the time). I understand the EGR VSV opens during light throttle. What would happen if that was bad? Wouldn't it be the same as removing the EGR vacuum line?

 

VSV is on or off. If off then vacuum is off.

The valve position should adjust with engine RPM, throttle position, etc.

If too much EGR gas then engine will have problems.

Any code for EGR valve position sensor?

Are there any wiring issues, issues with the wiring harness connections, etc?

 

Can a bad VSV cause the EGR position to let too much exhaust in (can it be providing too much vacuum?)? There isn't any difference between the old & new EGR. They both caused hesitation/misfire on light throttle. I don't think it is electrical just for the fact things change when I remove the EGR vacuum line. Just curious what determines how much the EGR valve opens when the VSV is "on" (light throttle)?

 

VSV is on or off.

The EGR valve would respond to the ECU based on a host of inputs to the computer. The ECU would gain feedback from the valve as to how much is it open based on the valve position sensor.

Have you checked the electrical plug connection to the EGR?

 

No, other than making sure it "clicks" onto the female end. How do I know if it's getting voltage?