service engine light

[wsp623]

My service engine light is continually coming on and off in my 99 Grand Prix. I took it to my local Auto Zone and a p1404 code came up indicating that it was either an IAT circuit malfunction or an EGR temperature sensor. They tested the IAT sensor and it seemed fine. My question is could it be my EGR temp sensor and if so which one? isn't there two of them? The car seems to be misfiring at low rpms with the rpms jumping anywhere from 800 to 2000 with myself maintaining a steady speed on the accelerator. Another problem I encountered the other day I was sitting at a stoplight and the car stalled on me it did this probably three times at the same light. When I took off from this light the car was really stuttering. Any input would be greatly appreciated.

[BIG-L]

Originally Posted by wsp623

My service engine light is continually coming on and off in my 99 Grand Prix. I took it to my local Auto Zone and a p1404 code came up indicating that it was either an IAT circuit malfunction or an EGR temperature sensor. They tested the IAT sensor and it seemed fine. My question is could it be my EGR temp sensor and if so which one? isn't there two of them? The car seems to be misfiring at low rpms with the rpms jumping anywhere from 800 to 2000 with myself maintaining a steady speed on the accelerator. Another problem I encountered the other day I was sitting at a stoplight and the car stalled on me it did this probably three times at the same light. When I took off from this light the car was really stuttering. Any input would be greatly appreciated.

From the site I use for OBD II ,it is saying that it's a problem with the EGR valve,but to get closer I would need the 3rd,8th and 10th digit in your VIN #


~Larry~

[wsp623]

my vin #'s are as follows in order 2, k,and x

[BIG-L]

P1404 EGR Valve Circuit Performance Actual Position Greater Than Commanded

This is a new one on me sounds as if the EGR valve maybe sticking or stuck.
Try tapping on and around it with the handle end of a screwdriver, it's not uncommon for a piece of carbon to get stuck in there.If that fails it maybe time to replace the EGR valve

My question is could it be my EGR temp sensor and if so which one? isn't there two of them?

I think you are refering to the O2 sensors.One in the rear exhaust manifold and the other is located after the cat.We only have one EGR valve located at the backside of the motor by the transmission and the firewall.Here is a picture of the EGR valve,not sure if you have a S.E/GT or GTP but they all look about the same,just the S.E is a cheaper part then the GT/GTP

Also before replaceing it, id pull it out and see if it is carboned up,might be able to clean the pintel valve to get it to operate again.

Not sure if I helped you out much.

Good luck!

~Larry~