misfire

:banghead: I have a 96 Windstar it misfires now and then. I went and pulled the codes, and the codes that I got were P0401-egr flow insufficient and P0304-cylinder 4 misfire detected. Being my misfiring was isolated to just one cylinder I replaced the coil pack, spark plug wire, and the plug. It still didn't cure the problem? It was suggested to me that my problem is in the injector. I don't think this is the problem. I also would like to add that when my misfiring occurs my check engine light starts blinking. I am told this is caused by unburnt fuel in my catalytic converter. I'm leaning to the thought that the problem is my DPFE and plugged exhaust ports in my intake manifold. Can anybody help me. Feedback requested. Thanx.

I would guess that your problem is clogged EGR ports in the lower intake manifold. You will need to remove the big black upper intake manifold to get to them. Not a difficult job. With the upper intake manifold removed....you will be able to see 1 small port for each cylinder. It is in the port that is always open. I have pictures at http://community.webshots.com/album/201931518cScpNK from when I cleaned mine.

I got the same P0304 code....and blinking Check engine light. What happens is....the EGR ports start to clog at the Cylinders closest to the EGR valve....with cylinders 1 and 4 being the last open ports. So cylinders 1 and/or 4 get all the EGR gasses......causing the missfire. The tar substance that clogs the ports seems to be just at the port....and not down inside the passage that goes to the EGR valve. I did clean the whole passage.....but found that it was not bad at all.

:banghead: I have a 96 Windstar it misfires now and then. I went and pulled the codes, and the codes that I got were P0401-egr flow insufficient and P0304-cylinder 4 misfire detected. Being my misfiring was isolated to just one cylinder I replaced the coil pack, spark plug wire, and the plug. It still didn't cure the problem? It was suggested to me that my problem is in the injector. I don't think this is the problem. I also would like to add that when my misfiring occurs my check engine light starts blinking. I am told this is caused by unburnt fuel in my catalytic converter. I'm leaning to the thought that the problem is my DPFE and plugged exhaust ports in my intake manifold. Can anybody help me. Feedback requested. Thanx.
:cwm27: thank you wiswind for the advice. we saved a lot of $$ because of this wonderful internet chat thing called Automotive Forum! It will be done as suggested this weekend so I will post the results after that. Thanx again for your help. God bless you.

I recently got p0302 cylinder 2 misfire on my 2000 3.8 .
I changed plugs, wires and coil pack and still got the code. :banghead:
I being lazy and cheep took a short cut to cleaning EGR. ports.
I removed wipers cowl and cover very ease to do.
Then removed upper intake cover, air filter and EGR valve.
Then I took a household canister vacuum with that plastic long skinny end witch now one knows what it is for anyway, and put it next to the EGR port as I picked at the build up with a dental pick.
Then I vacuumed out the port where the EGR valve goes. :smokin:
Worked great will let you know if code comes back as I am going on a road trip this weekend.
Bill

:iceslolan
Code is gone for good problem fixed

I would guess that your problem is clogged EGR ports in the lower intake manifold. You will need to remove the big black upper intake manifold to get to them. Not a difficult job. With the upper intake manifold removed....you will be able to see 1 small port for each cylinder. It is in the port that is always open. I have pictures at http://community.webshots.com/album/201931518cScpNK from when I cleaned mine.

I got the same P0304 code....and blinking Check engine light. What happens is....the EGR ports start to clog at the Cylinders closest to the EGR valve....with cylinders 1 and 4 being the last open ports. So cylinders 1 and/or 4 get all the EGR gasses......causing the missfire. The tar substance that clogs the ports seems to be just at the port....and not down inside the passage that goes to the EGR valve. I did clean the whole passage.....but found that it was not bad at all.
I replaced the spark plugs,wires, coil pack,and cleaned the EGR ports out with a vacuum like instructed (4 out of 6 were clogged), replaced the upper intake gaskets, put it all back together and drove it, still ran rough and didn't like to start til the 3rd or 4th try-but not blinking c.e.l. yet. I would like to add after cleaning the EGR ports and testing it I didn't get the misfire code but got P0102 MAF circuit low input and P0402 EGR flow excessive. So we researched some more and found we had an old DPFE aluminum, replaced the DPFE-seemed to be running better than ever since I bought it used a few mo. ago.Then the next day I drove it 20 miles to work ran fine on interstate. After work I got gas & washed it (which always seems to follow with misfiring) and sure enough it was misfiring -went to pull the codes and still got the P0304 misfire detected Cylinder 4, and P0102 MAF or VAF circuit low input?? :dunno:What else is left? Anymore suggestions?

I have pictures in the link that I posted.....on how to clean the MAF....and I would recommend trying that. Also make sure that all your connections are in place.

I did have a misfire caused by crud on the spray end of the fuel injectors... I had to remove them and spray cleaner into the "cap" on the end of each fuel injector.

I would also start the car when it is TOTALLY dark outside.....and look around under the hood.... Look for any sparks when you are getting the mis-fire.

I have a co-worker that installed new "Premium" spark plug wires that he paid a lot of money for. Shortly thereafter, he started having misfire problems. I was trying to advise him for about 6 months on what to try......
He cleand this and that......
Then he looked under the hood with the engine running in his dark garage.......looked like a city under the hood...around his new plug wires...... He replaced his "new premium" plug wires.......and it solved his problem.
Perhaps the car wash gets enough moisture at the right place.........

I have pictures in the link that I posted.....on how to clean the MAF....and I would recommend trying that. Also make sure that all your connections are in place.

I did have a misfire caused by crud on the spray end of the fuel injectors... I had to remove them and spray cleaner into the "cap" on the end of each fuel injector.

I would also start the car when it is TOTALLY dark outside.....and look around under the hood.... Look for any sparks when you are getting the mis-fire.

I have a co-worker that installed new "Premium" spark plug wires that he paid a lot of money for. Shortly thereafter, he started having misfire problems. I was trying to advise him for about 6 months on what to try......
He cleand this and that......
Then he looked under the hood with the engine running in his dark garage.......looked like a city under the hood...around his new plug wires...... He replaced his "new premium" plug wires.......and it solved his problem.
Perhaps the car wash gets enough moisture at the right place.........
I attempted to clean the MAF sensor as instructed while doing so I realized the female end of the wire wasn't even clipped to the male part of the MAF sensor. So I'm assuming that's where my low input was coming from. I did clean the sensor out as instructed and problem has been solved. But I still continue to get code P0304-misfire detected Cylinder 4.??So now I would like to try to clean the spray end of the fuel injector as you suggested. Could you possibly break down how this is done, does the upper intake manifold have to come off to do this? Are there new seals that I need to buy? Is there any special tools needed? Do I need to relieve the pressure from the gas lines so on and so on.Can you break this whole process down to me so I can get a feeling of what I'm doing from beginning to end ? You guys are awesome :) :) thanx

do a search in this forum on fuel injectors....I listed what I did...not long ago.
You might want to get "O" ring gaskets for the injectors in case 1 gets torn during removal.
You DO need to release the fuel pressure....you do that at the valve that is located at the center of the front fuel rail.

You DO need to remove the upper intake manifold again.

I would clean all the crud that you can get out from around the injectors...so that it does not fall down into the engine.

I did not need to disconnect the fuel line from the fuel rails (takes a special tool)....I was able to lift it up and lay it aside.

There is a clip for each injector.....to connect the injector to the fuel rail.

Another option would be to have the dealer do the fuel injector cleaning......if you are not comfortable with it......

Be very careful about connecting everything back up.
What I did....was....once I had the fuel injectors back in place....and the fuel rail in place.....before installing the upper intake manifold... I turned the ignition key to "ON"....NOT START......and let the fuel pump bring the fuel system up to pressure.
Then I looked around very carefully for any sign of fuel leakage. Much more easily dealt with at that point...before having everything back together.

Also...be very carefull about connecting all wires and hoses back up. One small vaccum leak will send you hunting for another problem.

I am also wondering if you have a loose connection for the electrical signal to the fuel injector. I have read several posts on this forum about that.
You will find them in your search.

We are responding to let everyone know that we cleaned the EGR ports and didn't wait for the "problem-free" drive cycles to clear the codes. So after replacing the DPFE and cleaning the ports and waiting we have NOT had CEL on since!!Yeah! We didn't clean the fuel injectors yet however our van has 217K miles on it and it's running great! We love it! It's a good van :smile: