Matthewdbaker

My 1993 f 150 is reading code 33, which is the EGR valve. I cleaned it out to see if that would work and it didnt. So I got a new one and I also got the sensor. It is still reading code 33. I had the codes ran because when I put it into park after driving it for a little it revs up and down 3 or 4 times but then starts to idle just fine. Has anyone experienced this and if so could you point me in the right direction? I have also checked for vacuum leaks and didnt find any.

qdeezie

Check the vacuum hose that connects to the EGR valve. Probably has a leak.

Matthewdbaker

The one that goes to the sensor on top or the pipe it screws onto?

qdeezie

The one that goes from the outlet on top of the EGR sensor and runs to the EGR DPFE. A good idea would be to replace all of the stock vacuum hoses with new rubber or thick walled silicone hoses.

Once those hoses get old (and they are over 20 years old), they literally get as brittle as Pringles potato chips and snap even if you slightly brush up against them.

Matthewdbaker

I replaced the hose and it didnt work. So i've replaced like every part of the EGR and still nothing.

qdeezie

What brand is your EGR position sensor and what brand is your EGR valve? Non-Motorcraft EGR position sensors don't work with Motorcraft EGR valves.

qdeezie

Also, make sure your EGR valve position sensor is the right part number and it actually works. I was once sold a black (charcoal gray) EGR valve position sensor, when my truck used the light grey one. Also, I've had new ones right out of the box that were garbage.

Matthewdbaker

They are both brand new and made by the same company.

qdeezie

What about the EGR tube that runs from the lower intake manifold to the EGR valve? Those are known to develop cracks in them from time to time.

Matthewdbaker

How would I check it? It's not easy to get to and it has like a cloth type thing around the whole thing