1998 Ford Windstar OBD II code P1537&38 Intake Manifold

I drove my windstar for about 6 months before coughing up the $150 x 2 for both IMRC valves and didn't notice any problems other than the check engine light. The IMRC valves simply open and close portions of the intake manifold to regulate the speed of air rushing through their interiors. Closed valve = more air speed because of less cross-section area per unit volume of air moving. The explanation gets into physics and geometry calculations, which I'll leave out.

Realize that both IMRC valves function off of only one vacuum source, so having a leak in the diaphragm of one IMRC will cause the opposite IMRC to malfunction, too. Unplug the vacuum source to the IMRC, move the hinge, then place your finger over the vacuum vent on the IMRC. If the valve stays put, it's OK. If it moves, you found the one with the damaged diaphragm. Try rockauto.com for IMRC replacements (mfg = dorman) instead of your local Ford dealer. Ford (at least here in S. Florida) want !! $320 !! for each. Yea.....right.

Your lean code may be set by having a dirty MAF sensor. Remove the MAF, spray some brake cleaner or similar solvent to the two MAF elements to remove any burned-on dust. Blow with shop air being careful not to apply too much air pressure to elements (don't damage them), and re-install. Monitor fuel trim values on a scanner, if possible.

I doubt the lean codes have any relevance to the IMRC's.

I experienced a problem with the IMRC . The check engine light turned on and my car wasnt passing the emmissions do to the fact of the codes stated above which was one of The Intake manifold runner control. I tryed doing the air presurre thing and saw that the little lever wouldnt hold up and i fuigured that it was the one that was malfunctioning. You could fix the problem just by actually toying with them meaning moving the little lever up and down. (note you need to do it continusly for a while, your car must be ON while your moving the little lever up and down. You most do it for both of them in the same time. Mine just got stuck and this actualy took care of the problem. I checked with the computer device for the codes. and it showed that it was working. I disconected the negetave side of the battery for 15 mins and conected it and drove for 30 mles and the light didnt show up and passed my emmisions :). I hope this helps. you might get lucky and your IMRC is just dirty and stuck. you will save a good 400 dollars.