P0174 code Engine light comes on and when hooked to code reader I get a P0174 code. Lean mixture (Band 2)

I've had this problem for months, on my 1998 windstar 3.8 liter...I would clear the error with a OBD2 port device...

Check engine light may not happen again, until I drove 5 miles, then again 50 miles before problem came back...Always same error P0174.. Van ran ok..

I just looked under the hood, and there is a Rubber Elbow, right on top of the intake manafold, it joins to a plastic tube that goes to other hoses towards the firewall. The rubber elbow was mushy, not hard..Kind of decaying, due to oil residue?..I took off the badly cracked elbow (causing vacuum leak for sure) and replaced with a foot long 5/16th fuel line. I just looped the 1-foot fuel line hose in a circle, secured with couple wire ties and presto, elbow fixed with a piece of fuel line..I hope this solves my P0174 error, will find out this week. But I'm sure, the cracked rubber elbow must have had an effect on the vacuum system.

Several months ago, I went to ford dealer, when I noticed the elbow showing surface cracking, they said I'd have to buy an entire vacuum hose gizmo assembly, and All I need is the elbow. So I didn't replace the elbow.

I had the two codes, p0171 and p0174, lean mixture bank 1 and 2. I found this is a common occurance, I have a 1999, 3.8L 6 CYL. The cause is the isolator bolts for the intake manifold. The original equipment bolts had rubber material not compatible with oil, the replacement bolts have a oil compatible rubber seal. The replacement kit is available from am-autoparts.com, ( Chelmsford,Ma.) the whole kit includes the new bolts ($113 from FORD), the upper and lower intake manifold gaskets, the front rocker cover modified for the EGR valve, a new egr valve and hose, and another vaccum hose. The whole kit is only 79.95, free shipping, I recieved it the next day, to Barrington NH. The repair was easy and only took a couple hours using the most basic hand tools. anyway there is a good web page that helped tremendously, http://leckemby.net/windstar/windstar01.html have fun, easy and cheap, FORD dealer wanted 300 for the parts and four hundred for the labor. Should be a free recall due to their darn DUMB engineering dept. FORD is killing America.