Advice Needed: 2002 GP 3.1L 104k

[SassyGP]

Initial problem was poor acceleration between 15-35mph. Acted like it was going to stall out. Once past 35mph...ran fine but with a whistling noise coming from under the hood.

Diagnostic Codes thrown were 0404 EGR Open Position Performance & 0300 Misc Engine Misfire.

We replaced the plugs & wires. No change. Disconnected the EGR and it runs MUCH better BUT still with a loud whistle on acceleration.

My question is:

Can you tell me how to clean the EGR? I have access to a garage on our base (husband is military), but need instructions.

Thanks in advance.
M

[GTP Dad]

Welcome to AF!!

Remove the egr and spray the underneath side where the valves are with throttle body cleaner. It will clean the carbon off the egr. Next look at the area where it egr connects. The passageways are probably clogged. See if you can clean these by just spraying them with throttle body cleaner and it should disolve the deposits. You may need to remove the phlenum from the car to get to the whole area. This is easy and can be done by just unbolting the phlenum and removing it. You will need to disconnect the throttle cables and associated plumbing and electrical connections. Once you have everything off spray the entire phlenum with throttle body cleaner and allow to dry. You may want to get a small metal brush and run it through the egr passageways to clean the carbon out. Once this is done clean the throttle body and the IAC motor. Don't move the pintle on the motor when you have it out or it may not reset. Replace everything in reverse order and the car should run better. I suggest you purchase a Chiltons or Haynes manual before doing this since it will better outline the process.

[SassyGP]

Hello
May I ask what the phlenum is?
Thanks: AJ

Originally Posted by GTP Dad

Welcome to AF!!

Remove the egr and spray the underneath side where the valves are with throttle body cleaner. It will clean the carbon off the egr. Next look at the area where it egr connects. The passageways are probably clogged. See if you can clean these by just spraying them with throttle body cleaner and it should disolve the deposits. You may need to remove the phlenum from the car to get to the whole area. This is easy and can be done by just unbolting the phlenum and removing it. You will need to disconnect the throttle cables and associated plumbing and electrical connections. Once you have everything off spray the entire phlenum with throttle body cleaner and allow to dry. You may want to get a small metal brush and run it through the egr passageways to clean the carbon out. Once this is done clean the throttle body and the IAC motor. Don't move the pintle on the motor when you have it out or it may not reset. Replace everything in reverse order and the car should run better. I suggest you purchase a Chiltons or Haynes manual before doing this since it will better outline the process.

[BNaylor]

What Lynn (GTPDad) means by the plenum is the upper intake manifold. On a 3.1L it is cast aluminum. The EGR mounts to it right about where the throttle body is located.

The DTC error code of P0404 means the PCM has detected that the EGR valve pintle position error is too large. The desired position versus the actual position is greater than 15%. It does not necessarily mean the EGR valve is stuck open or closed. Alot of times cleaning helps and may resolve the issue. At other times it does not because it is typically an electrical problem related to the EGR valve feedback and positioning circuits which feed back to the powertrain control module (PCM).

But to start, cleaning is a good idea. Also, when you remove the EGR valve you may need a new gasket. The same with the upper intake manifold gaskets if you decide to remove it for cleaning. Good luck.

One other suggestion is you should get the CAT convertor checked out. It may be the cause of the whistling noise because it is defective or clogged. You may qualify for a free CAT convertor based on your year model. The warranty was extended to 10 years or 120,000 miles, whichever come first. It may be the actual cause of the misfires and poor acceleration.