Rough Running 2002 Windstar

Oh gurus of Windstar wisdom, I hope you can shed some light on my problem. First a little back ground. I have 02 Windstar that had been relatively trouble free until recently. It has about 52K miles and is driven very short distances during the week, <2 miles each way. About 3 months ago I got the p0171/0174 codes. I replaced the isolator bolts. While the intake was off cleaned the EGR ports in the intake, none were blocked but a few were dirty. I cleared the codes and it ran fine for about a month. It started running rough one day and progressively got worse. The CEL started blinking and then stayed on. I had a p0301 code I replaced the plugs (with motorcraft) and wires. It ran a lot better but would hesitate/run rough especially at 35-70 mph under a load. Idle was a little rough not like at speed. I was not sure what was going on since the CEL was NOT coming on.
Next I thought it must be clogged injectors, so I took it to have the three part fuel injector cleaning done. The idle was smother and it ran great until the next day, same problem, runs rough at speed and it is not constant. It will rough for a few seconds then run ok for a while then run rough. It is much worse going up a hill or moderate acceleration. I don't want to take it to a mechanic (I have never had a mechanic work on any of my cars) but I don't know what to do next.

Thanks in advance

DrBill

P301 is the DTC for a misfire on #1 cylinder only. If the misfire was random, a P300 would be set.

Quote from Ford Manual with my comments in (). "The MIL will blink once per second when a misfire is detected severe enough to cause catalyst damage. (too much unburned fuel getting through to the converter) If the MIL is on steady state, due to a misfire, this will indicate the threshold for emissions was exceeded and cause the vehicle to fail an inspection and maintenance tailpipe test." (This might be the case if enough raw fuel got through and over heated the catalytic converter.)

If you have fuel and there is spark, there will be ignition. It would appear that you have taken care of the spark part of this. My bet would be a partially blocked injector on #1. A fuel pump that is weak will also lower the fuel pressure but it does it on all of them so even though I would check the fuel pressure just to make sure, I would purchase an injector and put it in #1 for less than $50 I think. My NAPA parts place stocks them. The plastic catches on the electrical connectors to these injectors break very easily. If one does break you can use a small electrical tie to hold the connector in place.

Next, I would clear the codes and run it to see what happens. If the misfire is cured and the converter is damaged, I think that the oxygen sensors will let you know if there is any other problem. I'm guessing that there will not be any other problems, but you never know.

Of course, I would watch for the more experienced heads that work on these vehicles all of the time to chime in here and offer some of their experience just in case I am all wet about this one.

Jim

Have you tried a few of the simpler things like fuel filter, air filter, and front O2 sensors?

When you changed your isolator bolts did you get the green replacement ones and also did you change the port seals?? You may had one of the vacuume lines in the back may have come loose.. You may want to have the ignition coil packs checked out.They have had issues in the past on alot of fords not just the windstar..

I would pull and inspect the plugs. Plugs can tell you a lot of what is going on in the chamber. Each plug should have a bit of white ash deposit ...any other appearance should lead to further investigation. Check the inside porcelain insulators for cracks ... indication of overtorqueing.

I will pull the plugs and check that. But if it was the plugs wouldn't the CEL be on? That is what is werid to me that the light is off and yes it does work on start up.
I did check the coil pack and the resistences were within the range quoted in the Haynes manual. I had replaced the fuel filter and air filter a few weeks before the problems started.

Could it be the fuel pump or possiblely a bad fuel filter? I am going to get a fuel pressure gauge and check that.

Thanks for all the ideas and suggestions
Bill
:banghead:
I would pull and inspect the plugs. Plugs can tell you a lot of what is going on in the chamber. Each plug should have a bit of white ash deposit ...any other appearance should lead to further investigation. Check the inside porcelain insulators for cracks ... indication of overtorqueing.

OOps, I thought you still had a code.

Fuel issues: filters, inlet screens, pump relays, etc ... do seem to often escape the PCM "radar screen".

I have a '96 windstar, so things are a little different.
I have read posts about problems with the fuel pump relay on newer windstars.
Problem can be intermittent, and the PCM does not monitor the fuel pressure or flow, so there would not be a CEL or code telling you of this.
The fuel pump relay is in the power distribution box in the engine compartment.
From reading other posts, you can determine which relay is for the fuel pump, and swap it with another relay that is identical (verify the number on the relay) and see if that helps. Also, check / clean the relay socket connections.

You might also buy a can of Berryman's Chemtool B-12 fuel system cleaner.
I bought the stuff in the metal can. Can is white with blue and maybe red print on it. Put the whole can into your fuel tank and fill it up.
You might need to run 2-3 tanks of gasoline with a can in each tank.
This is a solvent based cleaner. Most fuel system cleaners are detergent based cleaners, and are good, but sometimes a solvent based cleaner is needed.

Another thing that is good to check is the MAF.
You can clean it with a non-residue electronic cleaner. I have pictures of the MAF in my pictures. The sensor is located inside the plastic "bar" that goes across behind the screen that you see when you replace the air filter.
There is a hole in the front of one end of the bar, and another hole on the back side of the other end of the bar.
You want to spray the electronic cleaner into one hole, and have it come out the other hole.
This will flush the passage out, and clean the sensors inside.