I recently bought a 99 E-250 5.4 with 120,000 miles on it. The cel was on so I scanned it and got 0156, 0161 and 1406. I've changed the egr valve, the O2 sensor behind the converter, fuel filter and plugs. The cel is still on with the 3 codes and has a stumble from a dead stop once it warms up and feels like it kinda has a lack of power. Last week I was doing a job close to Baton Rouge and right about the time I got to the looting capital it started bucking and jerking in traffic. Checked the codes again and got misfire on the #8 so I changed the coil pack and injector on the #8 cylinder. Misfire code is gone but the other 3 are still there and it still has the stumble. The van is very clean, engine compartment is spotless so everything is easy to look at and seems to be all intact,hoses elbows etc.

Anyone have a idea what I should look at next??????

 

I assume you cleared all of the codes and you are still having them code up. I'd probably give it a real close inspection looking for chaffed wiring.

 

Yes I have. Everytime I change something I clear the dtc's.

 

Code P1406 would lead me to check the EGR hoses for blockage or being off.

 

Which downstream O2 sensor did you change? You have two and it should have been the driver's side sensor.

A P1406 is unlikely to be caused by them EGR valve. Usually it's a problem with the DPFE sensor or one of its hoses.

 

Ok so I checked the hoses again and 1 of the 2 bleck rubber hoses that come from the 1/2" pipe off the exhaust manifold to a black oval looking thing (has ref and hi written on the front) was off. I only saw it because I bought a new 1 at advance and was in the process of changing it out. The o2 sensor I changed was the 1 behind the cat. Somone else told me today that the egr solenoid (has a green and white or red hose to it) could be bad which was what I was at advance for but they didn't have it so I bought this oval looking deal and changed it. I wont know till I drive it back to BR tomorrow if it fixed it.

 

So that hose didn't fix it or changing that oval looking sensor. On our way to Baton Rouge I stopped at autozone and they had the EGR solenoid and I changed it out before we left the job on our way home and that was the CEL problem!! The van still feels like it has a little lack in power but not as bad as before.

 

Drive it for a few more days before you get comfortable.

An "EGR solenoid" shouldn't cause a P1406...

Of course, if you didn't reset the PCM when doing the DPFE work, the old codes would still be there...

 

Yeah I jinxed myself! lol I drove about 3 miles up the road after posting my last reply yesterday and now I have a P0402."A code P0402 most likely means one or more of the following has happened:

The DPFE (differential pressure) sensor is faulty and needs to be replaced
There is a blockage in the EGR (most likely carbon buildup)
The EGR valve is faulty
The EGR valve may not be opening due to a lack of vaccuum"

I've changed the DPFE, EGR Solenoid and the EGR valve. I'm gonna take a guess and say I have a vaccuum leak or a cracked hose somewhere that I can't see or maybe I need to to take off the + battery cable and let the PCM reset. What do yall think?

 

Pull the throttle body and clean it, pay particular attention to the EGR ports.

 

Yea, ports in the throttle body elbow. You could suck test the valve as well.

Here's a diagram -

 

Ok so I pulled the throttle body off and cleaned it, cleaned the MAF and went over all the vac lines again. Egr codes are gone but I still get the 0156 and 0161. Could the o2 sensors upstream be bad and cause the downstream codes?

 

No. See post # 5 for the question you have not answered.

 

Oh sorry lol, I only see 1.

 

If you only have one downstream O2 sensor, that would explain why the PCM is complaining about the second downstream sensor it is looking for but not finding. You might want to double check both banks to see if each has a downstream sensor or if you have a single sensor at or after a Y-pipe.

I don't know what the stock setup should be for your particular version of that truck other than what the factory service manual has in it. I can only speculate that a previous owner either modified the exhaust or put the wrong PCM (or wrong calibration) in there if you only have one downstream sensor.

Perhaps someone with hands-on the E-250 can help out.