I don't think that you can free rev a 4.2L over about 2500. The PCM has a built in rev limiter when it isn't in gear. My 3.8L Windstar won't. Maybe the trans selector switch is telling the PCM that it is out of gear even when it is. Will it pull past 2500 in gear if you manually **** it into low or 2nd?
Have you done a leak down test to make sure no anti-freeze is getting into cyl #1 and fouling the plug?

 

Sounds like that mechanice needs to go back to basics. First he should of checked spark, then fuel (make sure the injector is firing), and then check compression. If it has spark, then I would suspect an injector problem. If spark and fuel good, I would suspect compression problem (burnt exhaust valve, flat cam ect...) No offense, but the guy that worked on your van is not a "mechanic", he would be called a "parts changer". Those are the people that give techs like myself a bad name. That engine is simple, the fuel control system is simple, and the ignition system is simple. Any high school kid in auto shop could figuire the problem out within two hours. Sorry for the venting, just tired of people grabbing a wrench, putting on overalls and calling themselves an auto tech.

Hak

 

After all your help, I figured it's only proper to fill ya'll in on the final diagnosis: Catalytic converters were bad. (I was surprised there was more than one- as it's only a single exhaust setup)

It only took the dealership two weeks to figure this out. ha.

So we're rolling once again. Thanks again for all the advice.

 

Glad you finally got it figured out. I'm guessing you got to keep your job?

 

Yeah, well we have a back-up van that I used in the interim-- a 96 E-150 with 300,000 miles on it. If that one had quit, then I'd have been out of luck; and believe me, it really took some effort to keep that one rolling- as it had been used and abused for years before I came along.

Examples:

When I checked the air filter, sand actually POURED out of it. (I just about cried when I saw that)

When I checked the spark plugs, they were so old that one of them was actually missing its upper electrode completely, and another one had its firing gap completely closed by carbon build-up.

There were some other issues that popped up as well, involving the sliding side door; the air conditioning; and a freak incident involving a loose bolt for the air pump, the pump pully, and the drive belt. But nothing that kept me off the road.

So, while that other van has been prone to problems, this older van really goes a long way in showing the potential for Ford. Even with the above examples of neglect, that engine never quit running. And since I replaced the filter, plugs and wires, (and drive belt) the thing runs like a top.

Kudos to Ford.