Hello, I have a 2001 E250 4.2 v6 giving multiple codes po300, po304, po305 and po306.
I have changed coil pack, ignition wires and plugs, still getting codes, low power and detonation, service engine soon light flashes and usually stops on its own but I have had to reset it once.

My transmission has been acting up and after a lot of reading I've read that a slipping transmission could cause the misfire codes.
Can anyone verify if this is true, I'm tired of throwing parts at the problem
Thanks I'm stating to loose it with this problem

 

Unplug the vacuum line from your EGR valve then plug the line with a tight fitting screw....

 

Unplug the vacuum line from your EGR valve then plug the line with a tight fitting screw or golf tee. Unplug your battery for a few minutes to reset the engine codes. Then go for a test drive.

If it's better, let me know and I'll tell you the secret.

If it's not better- then I'm no help.

 

thank you I will try to today

 

Thank you I will try that tonite

 

Pulled vacuum hose off egr and plugged vacuum line disconnected neg battery terminal for half hour hooked back up and tested, didn't make any differance.
Seems to run very smooth at idle but a on heavy acceleration I hear detonation but only under heavy throttle. Does anybody have anymore ideas?

 

Codes 304, 305, and 306- I believe that's cylinders 4,5,6 misfire. Also I believe those are the passenger side cylinders.

If I'm right about those two things, then I bet your passenger side catalytic converter(s) plugged up or failed.

My first idea was regarding the EGR ports on the intake manifold. I had to fix that on my 2003 4.2 V6 E250 a couple years ago. However, after your experiment results, I believe your EGR ports are ok.

However I feel pretty strongly about your catalytic converter(s). Every Ford I've had (made in the last 15years) has had a bad catalytic converter that lead to engine performance issues. (Well, my wife's 2010 Escape is ok. But I'm watching.) I JUST went through another 6month-long "diagnosis" with my V10 E350 having spark knock and performance issues. Replaced cats with straight pipes and all is well again.

Check my "facts" in the first paragraph and then proceed.

Make sure you keep us posted.

 

456 are on driver side. But I have heard people say if cat's are plugged you can test that by pulling the O2 sensor for a short test drive and see if the problem goes away, the lack of power makes me think you might be on to something. Did you have any recommendations on how to check the catalytic converters?

 

I checked mine visually. See my other post. It's very recent. Titled: V10 misfire something-eruther. Here in the van section.

 

I read about unplugging the O2. That's fine depending on where the excessive back pressure is.

My recent one was at the entrance to the 1st catalytic converter. There's no O2 sensor there.

I think you need a visual down into the entrance of the first cat.

Did you find my other posts? "2010 V10 pinging, misfire..."

I have pictures of the bad unit.

 

Yes just read about it, so removing the cats did the trick? My engine has O2 sensor before and after cats, so I wonder if I do this will the computer throw codes all the time? I've heard something about putting a resistor in place of the O2 sensor to remedy the code issue.
Anyways I am going to try pulling the O2 sensor or drop that side of the pipe off of the manifold today and see what happens, wish me luck!

 

Ok, so I heated up the bolts on left exhaust manifold (drivers side) and removed them, pulled the pipe down and used a large 3/4" bolt to block it down. Went for a test drive and wha-la no more missfire or lack of power. So now I know my catalytic converter is bad,that's the good news!
Now I have to deal with new cats or test pipe. Does any body know where test pipes are available?

 

Thank you im50fast

 

I had a lead from a racing buddy for an exhaust shop that would do illegal exhaust work.

For $100 cash (and he kept the old catalytic converters for scrap), he cut out all four and put in regular pipe. He even welded in new bungs for the O2 sensors. It took him about 90 minutes.

I learned a couple lessons with that. You probably read on the other thread my complaints/concerns for the new bad smell of exhaust. Though it's not quite troublesome enough to spend $500 on new catalytic converters.

Also it is definitely more noisy in the cab now. I was wondering if maybe he used cheap or thin wall pipe. There is one small leak in his weld about the diameter of a Q-tip shaft. I struggle to believe that is the cause of quite so much noise increase.

Yes my check engine light has been on ever since. But it runs great, and so far I've gained 1 mile per gallon.

Most importantly; I have my gas pedal back. :-)

 

Than you again, I was able purchase new cats from Rock auto for 523.00 going to install this weak, while I'm replacing the trans, I has 180600 miles so it's done its job