I have a 96 Windstar 3.8l that will start to "chug" and smell of raw gas after it has been driven for a period of time and is let sit for 20 minutesthen restarted (I have a friend with a 98 windstar that has encountered the same issue). I was told it wasthe fuel "boiling" in the fuel rails but find that hard to believe. I have had it into 2 reputable shops and have been given many possible causes (all to be covered at my $$$$...of course). Is there anyone who knows or who has pin pointed and fixed this before?

 

Could it be that you have one or more injectors leaking when you shut the engine off? If a fuel pressure drop test (koeo) shows that you loose pressure after about 20 minutes, then that may be the problem. Of course, finding it can be fun, but if let it sit for about 30 minutes, then remove the spark plugs, you might see evidence of it on them. As for the fuel boiling, I have never heard of nor seen that with this engine, besides, this is a fuel return system and as soon as you turn the key on, you have 40 psi setting on top of the injectors and if any problem with fuel boiling, it should be cured as soon as it starts. All vapor returns to the tank.

 

I have replaced all injectors (had shop clean plenum while off and doing injectors), new fuel pump, new plugs, checked wires, new coil pack, fuel regulator, MAF sensor&new converters (found plugged while having vehicle checked atrepair center) All withinpast year.

The "chugging" happens after it is warmed up and driven for a period of time (ie. shopping, running errands, etc.). After sitting 17-20 minutes (not less than 15 minutes but not more than 30 minutes) will start to "chug" for 30 seconds and smellof raw gas until running smooth (may have contributed to the loss of converters). I have even had lean bank1 and bank2 codes come up (this is more noticable during the summer when it's warm out). I have been chasing this down for the past 2 years and have noticed it happening more often now(sometimes even during cold weather...just not as noticable or frequent).

As mentioned, I have been chasing this down for the past 2-3 years. I have had it into 2 reputable shops and 1 dealership. I'm hoping to find someone who has had this issue and corrected it. Any other thoughts and/or feedback welcome.

 

Is the engine running during the "17-20 minute sitting time"? Also, why would you replace all of the HIGH dollar items, but never replace a $35 set of plug wires? You could have spare leakage causing the problem due to weakplug/coil boots. Sparl leakage will tend to appear after the boots get warm and expand around the plugs. I would replace these and use a light coating of dielectrical grease on the insides of the boots. This will also eliminate moisture related spark leakage. Also, pull the vacuum line off of the fuel regulator and see if there is fuel in it. If there is, then the regulator diaphram is failing/faild and could also cause this problem.

 

Do you have to put antifreeze in it every few months? Like you have a minor leak?

 

This is what I was thinking, since these were popular for head gasket leaks, but that doesn't explain the fuel smell. However, many of these Windstars will stumble or "chug" after sitting if there is a head gaskets leak..........until the coolant is blown out of the cylinders(s) that is leaking

 

Have also seen these leak coolant into the intake manifold,then coolant sits on top of the valves or seeps into the cylinders.

 

I'm going to have the cooling system pressure tested and then I'm going to have them pull a sample and test it for exhaust (i'm told if there is an internal coolant leak "it should" show-up on this test). I had the converters replaced this summer (I'm told converter failure is also apossible sign that there is antifreeze entering them. However, it does have 190k miles...age and time alone may have been the cause forconverters failing). I'll keep posting as I try things. Thanks for your thoughts and ideas!

 

It was the lower intake! I had it done this past week by a shop ($780). It only took me 4 shops and $2800 to figure this one out...and of course your excellent advise!!!One shopwanted $5000 to replace head gaskets and exhaust system...obviously was not needed. Thanks for the insite!