Coating or no, stuff gets stuck to the interior of the intake. I think Yitzy has dscribed this already in another posting. (Cleaned up stuff that looks like used oil from the throttle plate...) With just PCV, it might be possible to spray it off with some kind of cleaner. With EGR, the gasses really bake themselves onto the walls. Some EGR designs have the exhaust passges cast right into the intake manifold, adding that much more heat to it. With a toothbrush, the bristles should not be all that damaging to any coatings that might need to stay there. But my feeling is that the coatings have long worn off from being attacked by the PCV gasses.

Yitzy, I would also check to see if your PCV valve is working properly. Your description sounds like it was ventilating too much from the crankcase into the intake.

 

It is a new PCV valve. How do I test it? Also, once i take it out anyway, should I put anything down the hole?

 

never had Ford's No So Good Idea of Slic ***** 50 Teflon frying pan coating in the throat of the throttle body work to prevent crud build up for my rigs....
always had to clean them....noi wire brushes or acid please....just a good quality throttle body cleaner or a can of Berrymans B12, paper towels and shop rags

not any good ways to test a PCV with diyer tools....need a vacuum gauge connected in a T after the valve on a long line into cabin and observe vac. while driving....but why bother, they're cheap and easy to replace....your new one is ok


clean the ring packs with the can of Berryman B12 injestion and soak....will solve any blow by problem from sticking rings
worn cylinder walls and rings are rare in 4L's....hardly ever see a smoker in this engine

the O2 codes indicate your MAF is toasted with crud....clean or replace

get a Chilton's Aero manual from any auto parts store or online for detailed repairs and locations

 

Thanks! The MAF will be my next point of attack. I already have both the Chilton's and Haynes books for my Aerostar, got them real cheap on eBay right when I got the car.

God bless you, and in case I do not get a chance to post again soon, Happy New Year and Happy Holidays to you and all!

 

Okay, the good news and the bad. I found out what was wrong, and we were all way off target. On the other hand, it took some money.

After 3 weeks of rough idle and stalling the van stopped in middle of driving. Thank God it was on my way HOME from work, and it was only 1 block away from home! I called my father (a retired Mechanical Engineer who fixed vehicles in the army) and after reveiwing the symptoms, he diagnosed the Fuel Pump. He also told me how to get it the one more block home! I turned on the car without starting, waited a few seconds, then turned it off. Repeated this 5 or 6 times, which provided wnough pressure to run the car for about 20 seconds. Throw it into Drive, go until it stalls, and start again.

I looked up in Chilton's and determined that the feul pump is inside the Gas tank. No way I can lift the van high enough to do it myself. Looked up the part on AutoZone and saw that it cost over $100. AAA towed it to a mechanic (had difficulty finding one open on Sunday December 24!!) who put it on a pressure test and confirmed the diagnosis. He finally finished the job at 3:10pm, and I start it up. It is still rough. He puts back on the pressure test and yells Whoa!! There is the problem. The pressure reads 80psi and is fluctuating wildly. I could not find the proper pressure anywhere in Chilton's, so I have to take the mechanic's word that steady 40psi is the correct value. He diagnoses a Fuel Pressure Regulator.

Bad news. It is 3:10pm, and all of the suppliers closed at 3pm due to Christmas Eve!!! I had to go back home until Tuesday, but I did drive the van home. He warnde me not to drive it too much since the fuel pump could get killed again.

Anyway, after a few more hours wasted on Tuesday, it is finally fixed, and running like a charm. Apparently nothing else was wrong!

I never would have figured this out myself if the pump hadn't broken, since no one suggested the fuel pressure, and I had no tools to test it anyway.

Thanks everyone for your help!!