2000 Windstar 171/174 then more codes/issues

I started with 171/174 codes indicating lean banks 1&2. I unknowingly replaced the DPFE sensor, then started reading around and learned about the intake manifold leaks. I bought a kit from 1aauto Shop 1A Auto® for Ford Windstar 3.8L Intake Manifold & Valve Cover Repair Kit 1999-03 for your Windstar and replaced all of the port seals, other seals and isolator bolts, along with the front valve cover, PCV valve and hose. The check engine light was out for the first time in several years. The van actually was running decent, not perfect but ok for about a week. Then one day it started running "rough" again then the next day it was ok again. Well now the rough running is worse then the check engine light cam on again, darn! Sprayed some carb cleaner around and can't seem to find any vacuum leaks. So got the codes read;1504 idle air control circuit faulty. Also 302,303,305 cylinders 2,3&4 misfires. plugs have not been changed and mileage is 90,000. I bought double platinum plugs tonight along with the coil pack and figured I would install both figuring if the coil pack possibly is not bad it will go soon enough and I may save myself the job later. I did not buy wires. Believe me I am no car mechanic; I can read and follow advice and it has gotten me this far...so any feedback on other things to be aware of or other maintenance items that I should be considering at this point. I did clean the MAF with some throttle body spray and replace the air filter and that is about it. Also got a loud plastic like tapping sound coming from th upper intake. Does anyone feel that the 2 piece upper intake could be the cause of a loud, plastic like, tapping sound? It follows the engine speed and is intermittant. Happens alot while decelerating. Thanks in advance for everyone help; i have learned a ton about my car here and saved alot of money.

I'm no expert either but have the same 2000 year van and did the DPFE change and intake manifold rebuild as you did several months ago to clear the P0171/174 codes. My codes cleared and have not returned, thank goodness as my emissions test is due next week.

The plastic rattling sound you hear sounds like the symptom others have described where the upper plastic plenum assy. cracks or breaks and makes this noise. Did you inspect it well when you had it all apart? Did it go back together well w/o any binding or possible assembly damage?

The part in your post that concerns me is the cleaning of the MAF sensor with TB cleaner. In researching some DIY activities on my Windstar, cleaning of the MAF was mentioned a lot but with warnings about only using a special cleaner designed just for MAF. I bought a CRC product and cost about seven bucks a can at AutoZone. I've read where any other type of cleaner will kill the $100+ MAF sensor as it is easily damaged by the wrong type of chemical spray. Hope yours is okay.

Some of the other great knowledgeable posters will surely know about the new codes you're getting now and help you out. Watch this thread, I am sure you will get some good tips to follow.

Code 1504: Idle Air Control,(IAC), system did not respond properly to PCM command. The PCM expects to see battery voltage when the solenoid is commanded off and under 1 volt when the solenoid is commanded on.

Normal solenoid resistance is 6.0 - 13.0 ohms.

If the solenoid was removed during the isolator bolt install re-check the electrical connector and mounting.