Ford Repair: 2001 Ford Windstar LX 3.8L, 2001 ford windstar, ford windstar

Question
QUESTION: My van is giving a code (engine is running too lean on bank 1 and bank 2. I replaced the fuel pump due to low fuel pressure. That did not fix the problem. the car is missing and jerking and backfiring when i get down on it. Could this be and oxygen sensor or could it be a cracked intake manifold? the diagnostic test did not give and exact sensor failure

ANSWER: scanning for codes never gives an exact answer that is not the purpose it gives  you a direction to follow-lean codes on windstars are usually vacuum leaks around bottom of upper intake-mainly cold-clogged egr ports in lower intake which will cause misfire-could be's cover a lot have it checked by a reputable garage-by the way what was your fuel pressure. you may have more than one problem.

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QUESTION: Fuel pressure was 38 psi while running. Also when engine is idling, i manual work the throttle from under the hood, when i do this for just a second you hear a sucking sound. I don't know if this will help,but when engine is idling with the defroster on, and the compressor clutch cycles, the car starts missing and you hear that sucking sound for a second again. it's almost like the car only does this when under strain. engine sounds fine when just idling. I have also changed the plugs and wires. Thanks alot. What can i do about the cold-clogged egr ports(what would be the repair requirements if this is the case?)

Answer
fuel pressure spec running is 28-45 most run around 35-40

the sucking noise after cracking throttle or when rpm changes is normal
to repair leaking intake seals or clogged ports you have to remove upper (black plastic) manifold-replace the sealing rings on the bottom and seals around all the long bolts this took me a while to learn after pulling upper plenum one day three different time i realized i was leaking around the bolt channel when i smoked tested it. when you have the plenum/upper intake off you will see one port in each cylinder hole in intake they probably will be clogged or most of them will-remove egr from end of intake then take a blower and blow out each port while blocking any that are open and the carbon will blow out of the intake where you took off egr valve-what happens is some ports will clog and one or two will be open and when the computor commands egr to open all the exhaust gasses which should be divided between six cylinders will all flow through the open one or two causing a lean mixture on those cylinders and it will cause a misfire-just be sure to clean ports and replace seals-good luck.