Fixed my 0401 code. Now I got 0300. Any ideas?

[Declansdaddy]

So I have the p0401 code which was EGR flow insufficient. I took the throttle body apart and sure enough the ports were stopped slam up. I held the EGR port vertical and filled the pipe with carb cleaner and not a drop came out the other end (2 smaller holes). Got that all cleaned out good and reassembled and went for a test drive. Under acceleration my CEL flashed and then stayed off. Got home and checked for codes and the 0401 code was gone however I'm getting a p0300 random misfire code. I'm assuming this means it's random cylinders rather than a specific cylinder. Any ideas on what could be going on? FYI it's a 99 4.6 and I put plugs and wires on it less than 500 miles ago.

 

[stamp11127]

Vac leak, did you use a new gasket?

 

[Declansdaddy]

Yes all new gaskets, new hoses on the DPFE sensor. I'll spray some tb cleaner around the TB with it running and see if it revs up any I guess.

 

[stamp11127]

Are you sure the hoses are not crossed on the DPFE sensor?

 

[Bedrck47]

recheck the electrical connector on the DPFE, make sure its fully seated.

 

[Declansdaddy]

The hoses seem to only go one way. One is bigger than the other so I assume it's big port to big port. Connector seems in good and I dielectric greased it as well. Tried to spray carb cleaner around the TB and no change in rpm. Went back through and checked plug torque and made sure the wires were on good and all seemed in order. Still got the miss. Only seems to happen when I first start it up, it stumbles for a few seconds. That seems to clear up but if I hit the throttle the motor shakes like its missing and the light blinks.

 

[stamp11127]

Dielectric grease is an insulator and I personally don't use it on anything other than spark plug boots. If you have an inductive clamp timing light you can use that to monitor each plug wire as it is firing to locate the miss.

 

[Declansdaddy]

Also I should add it was doing the stumbling and shaking before I did the TB clean I just figured at first the carbon was the reason. Very annoying. I really don't want to have to pay a shop to figure this out.