misfiring on cylinder 1,3,4, and 6

1996 FORD WINDSTAR
2,197,893 MILES • 3.8L • 6 CYL • AUTOMATIC
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MENIKA22
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  • 1 POST
My vehicle listed above is misfiring on cylinder 1,3,4, and 6 along with my manufacturer control and system too lean banks 1 and 2. I've already replaced the spark plugs and boots and still have these codes coming up. my van will completely shut off while I'm driving and when I come to a stop it starts right up. when I turn it over it also shakes like my front end is going to fall out. what do I do to fix it to where these codes aren't coming up?
Jun 19, 2021 at 9:39 PM
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JACOBANDNICKOLAS
  • CAR REPAIR CONTRIBUTOR
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Hi,

The idea that you have a lean fuel mixture on both banks means either you have an engine vacuum leak or the fuel pump isn't providing enough pressure. Either of those things can cause a misfire and rough running.

If I had your vehicle, the first thing I would check for is a vacuum leak. Here is a link that shows how to do it:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

If absolutely no leaks are found, I would next check fuel pump pressure. Here is a link showing how that is done;

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you look at pic 1 below, I highlighted the Schrader valve where the fuel pressure gauge will attach. I realize most people don't own a fuel pressure gauge, but oftentimes a parts store will lend you one to use.

The manufacturer's recommended fuel pressure is 40 psi.

Try these things and let me know what you find or if you have other questions.

Take care,

See pic below.
Image (Click to enlarge)
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Jun 20, 2021 at 9:06 PM
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