My Monte threw the P0401 Engine Code last year. We cleaned the ports and put on a new EGR. It threw the light again. The car was running fine and no trouble with the gas mileage, so I wasn't in that big of a hurry to take it to the shop or anything.

Lately it has developed a slight miss, more noticeable in park or at idle at a stop light. We once again cleaned the ports to include the EGR Tube that goes to the exhaust manifold, as well as removed the EGR and cleaned the upper port. My dad didn't trust that the last person cleaned there good enough. He said it all was really clean. He did find a vacum hose running to it that was flat and worn out and we replaced it. It's still throwing the code and has the slight miss.

In the last two weeks we have done the following - some of which are probably non related, but throwing it out there.
*New Plugs and Wires
*Fuel Filter
*Cleaning noted above

It has 99,600 miles on it and I have been diligent in keeping up with the maintenance as outlined in the owners manual.
3.4 Engine
No modifications.

I have at various times during the different things we have tried ran Chevron Cleaner or Seafoam, in the gas.
After dad cleaned everything this last time, I ran Seafoam.

Any help/suggestions would really be appreciated. I hate to take it to a shop when there is something we can check on our own.

Thanks!
Melinda

 

check for vacuum leaks with a can of carb cleaner. with engine running in park pop the hood and mist carb cleaner around the engine if you have a bad intake gasket it'll rev up