Many people with Windstars have this same problem. And Ford made it worse I hear in 99. imrc is a $267 part and only from ford! add labor @ $90

Engine codes P1537 and P1538, IMRC stuck open thread has some too.

Part costs $267. Add Labor of $90.. and there you go on your merry way. I wouldn't have bothered, but the emissions test needs to have the Check engine light off!

Google the IMRC on Google to see other ways/people complaining!

http://www.automotiveforums.com/t477948-p1538_imrc_stumper. html