CEL P0402

Alright guys, I’m in need of some desperate help here. CEL came on and threw a P0402 - excessive flow code. Motor started running really bad and heard a slight knock coming from what sounded like the rear header area. Read up on TW on some other threads and tested out a few theories.

Pulled the EGR valve and cleaned it. Mechanic buddy said put solvent in and if non leaks through then it’s good. Put a new PCV. New EGR vacuum modular. New VSV (green one under manifold). New vacuum purge switching valve.

Still haven’t been able to drive it for two weeks with the fear of knocking noise causing worse issues. Truck idles really rough and when I throttle up just a tad the knocking noise begins. I’m at the end of my mechanic fuse and ready to set the thing on fire. Anyone have similar issues? Any help would be appreciated. Thanks.

FYI - 1995 Tacoma 2.7L 4x4 about 12k on remand motor. Motor had approx 225k before the rebuild.

 

I'd block it off personally. You simply cut open a can of coke to make a gasket with no passthrough. See how it runs with zero EGR.

 

When you say gasket are you putting that from the throttle body to the EGR valve? Or at the bottom of the EGR where the tube bolts to it?

 

Either, the goal is to stop the flow, which ever is easier. The tin is easy to cut on a coke can so its ideal. I was taught this trick a loooooooong time ago and used to block the old 22RE's with it.

Your taco has EGR monitoring, but at this point its best to plug it off to assist in diag. The light doesnt matter right now, we just want the truck to run better.

 

Agreed. I appreciate the response and tip. I will have to give it a try. I hope it’s something simple and the knock isn’t a mechanical issue in the valves or something.

 

After some much stressful diag. It turned out to be a blown head gasket between cylinders 1&2. Pulled head and the block is warped in that exact spot. Hoping the company who did the original work and the remain company will warranty. (One year over the warranty but BS to blow at only 11k miles)