Summary: This auto repair blog post provides a quick easy way to check for a vacuum leak that can cause lean codes on Ford Windstars.

Ford seems to have more than it’s reasonable share of lean codes, the Ford Windstar is no exception. If all the usual suspects have been investigated and no leaks were found, there’s another possible cause of a lean code when diagnosing a Ford Windstar. At one time I had so many of these vehicles to work on… I kept a parts list! In my notebook, I kept a list of part numbers that made writing up an estimate for repairs much easier. Later, when I used the computer at work more I converted my notes over to a “Word Document” file that allowed me to copy paste. When you work Flat Rate, you learn to save time when you can!  Back to the subject at hand. In this auto repair article we briefly cover a common cause of lean codes on the Ford Windstar.

We recently wrote a repair article on Common Causes for Lean Codes and what to look for, that may also be helpful. This article covers a specific problem that many Ford Windstars have. Lean codes can affect both banks or just one. The intake manifold on the Ford Windstar has intake runner seals that are prone to leak. The runner seals, most of time can be checked easily with fuel injection spray. All the basics should be checked like in our other article, but if nothing else is leaking, chances are one of the intake runner seals will be the cause.

**Caution** When spraying the intake runner seal be sure to stay clear of the alternator to avoid starting a fire! If a change in idle or stumble results when spraying the seal, it has a vacuum leak. The one being sprayed in the picture above is in the front, don’t forget to check the back one as well. P0174 a lean code for bank #2 which is near the radiator on the Windstar. Lean code P0171, is a lean code that affects bank #1 which is near the firewall. If both codes are present, then obviously both of the intake runner seals are leaking or a different problem is the cause altogether.

Question: How do I remove the upper plenum? It’s a tight fit to remove it, because of it hitting the wiper cowl.

Answer:It is tight, but it can be removed without removing the cowl. When loosened, rotate the right side of the upper intake towards the front of the vehicle. Go easy because breaking the plastic channel is a possibility if it is forced.

Question: Do I have to replace the entire lower intake due to the seal leaking?

Answer:I dealt with aftermarket warranty companies, that were willing to pay for the entire intake. So, I never resealed the intake runners myself. I do know of a few other auto techs that were forced to reseal them occasionally because of the intake assembly being on back-order from Ford. Unbelievably, they used air conditioning o-rings to replace the ones that were leaking and they never had any comebacks that I’m aware of.

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