'96 Winstar 3.8L with P0304 code.

Hello everyone,

I recently discovered your forum. What a wealth of knowledge!

I have '96 Windstar with the 3.8L engine. About a month ago I started getting a CEL that would come on flashing then go steady. This would happen while driving sometimes at highway speed sometimes at city speeds. This is accompanied by a slight miss in the engine which can't always be seen in the tachometer. The engine starts and idles fine. I read the OBII code and it show P0304, misfire in #4 cylinder.

I have read numerous post on this site that have given me a lot of good information on what to look for as the cause. I have replaced the plugs and fuel filter. Still had the problem. I have checked the fuel pressure, shows about 35psi during idle. As I rev the engine up it goes to around 42psi then settles back to 35. When I let the engine go back idle the pressure drops to 28 psi the goes back to 35. If I pull the vacum line from the fuel regulator it goes to 42 psi. So, I think the fuel system is O.K.

I'm down to the point of pulling the upper intake manifold and checking for plugged EGR ports.

My question is do I have to replace the gasket on the upper manifold or is it reuseable? I have checked with Pep-boy's who said that they could not get the gasket. NAPA only sells a kit that has the upper and lower gaskets along with several misc. gaskets to the tune of $66.00. Also, I was thinking that while I have the upper intake manifold off I would check the Injectors. Do I need to replace the o-rings? Pep-boy's and NAPA both said that they did have them. The other thing that I have seen mention was talk about isolator bolts. Can anyone tell me what these are and if my '96 has them? I do have a Haynes manual and they are not specifically mention in there.

Sorry to be so lenghty! I figure the more info that I give you guys the more it would help you answer my questions.

I would appreciate any and all input!

1. You do not need to worry about isolator bolts....the issue with those is on the '99 and newer windstars that use a different intake manifold.

2. The MOST likely cause of your problem is the EGR ports. P0304 is a missfire on cylinder #4. Your CEL will flash when this happens....
Cylinder #4 and #1 are the farthest from the EGR valve. The ports start to clog closest to the EGR valve.....so now most of the EGR gasses are going into cylinder #4 and possibly #1. Which is causing a missfire. Put a shop towel, etc into each passage below the EGR port....to minimize junk going on down.
The upper manifold gaskets are reusable.....I did replace mine....but did not need to.
You can buy new ones at www.rockauto.com


4. You may want to remove and clean the spray ends of the fuel injectors. You will need to release the pressure in the fuel system....which can be done at the little valve at the center of the front fuel rail. I did NOT have to disconnect the fuel rail from the fuel line....I lifted it off of the injectors and set it aside. There is a clip for each fuel injector / fuel rail connection. Clean as much junk from around where the fuel injector goes into the head before removing the injectors....you want to minimize any junk going down into the engine.

You can do a search on EGR ports in this forum.....and find a lot of posts.

I have pictures of various repair projects for my '96 3.8L, including the EGR ports at http://community.webshots.com/album/201931518cScpNK

wiswind

Thanks for the reply.

1. O.K. on the isolator bolts.

2. Good to know that the gasket is reuseable. I'll go ahead an pull the upper manifold to clean the EGR ports. I'll inspect the gasket while its off and if it need to be replaced I'll order one from RockAuto. Thanks for the tip on that site!

3. I'll go ahead and clean the spray end of the injectors while I'm at it. I've read several post on cleaning them. Seems to be a minor task once you get it tore down.

I had looked at your pictures on webshots before I post the original message. Really helped me a lot in understand how things go together. I like the Haynes manual that I have but it does have some short comings, not a lot details photos such as yours. Thanks for taking the time to take and post all of those great pictures.

BTW read a post earlier about a simple test to help isolate this problem. Simply pull and plug the vacum line off of the EGR valve then take the vehicle for a test drive. If it doesnt miss then the problem is more than likely the EGR ports. SO, wife had to go to the store awhile ago so I pulled the vacum line and let her take the van. Guess what? No miss!!
SO its time to clean the EGR ports.

Thanks for all of your help. :smile: