I'm having some problems with my Aerostar minivan and am hoping for> some guidance on what to check next.>

This minivan ('94 Aerostar 4.0L) has been plagued by problems for the> last year or so and the most recent no-start (about a month ago) was> resolved by replacing the catalytic converter. It had failed and> clogged, causing a blocked exhaust and preventing the vehicle from> running.>

About a week ago the van started showing the same symptoms as with the> catalytic converter failure. That is, rough idle, stalling at> redlights, hard start, and (eventually) won't start. As my wife was> driving it home one night last week it stalled on a side road and> hasn't run since.>

I towed it home that night and have replaced the following:> 1. Fuel filter (actually changed that a couple of days before it died> and it made no difference in the symptoms)> 2. Air filter (I have removed it and won't be re-installing it until I> can get the vehicle to run while sitting in my driveway)> 3. Spark plugs (all 6 and they all needed it - the old ones were toast)> 4. Spark plug wires> 5. PCV valve (old one looked ok, but I replaced it anyway)> 6. Throttle position sensor>

Still no luck. The first time I try to start it I can usually get the> engine to fire and run as long as I keep my foot on the throttle.> After that it won't start again until it sits for a while.>

I'm convinced it's being flooded with gas but I'm not sure why that is> happening. I have noticed that fuel is coming out of the throttle> housing into the air intake and eventually down to the air filter after> a few attempts at starting it.>

I'm fairly certain it has spark - when it's "dry" (sitting overnight)> it will fire if I have my foot on the gas pedal and it will try to run> for as long as I keep the pedal down. If I back off the pedal it dies> and won't start again until the next day.>

I suspected the new catalytic converter or muffler (or both) had failed> and created a blockage so I've tried detaching the exhaust downpipe> from the manifold and that made no difference - still won't start.> I've also checked the exhaust pressure coming from the tailpipe while> trying to start it and that feels normal.>

I've looked for vacuum leaks, cracked hoses, disconnected sensors, just> about everything I can think of. I'm running out of things to check so> can anyone offer some advice on what to do next?>

Any help would be appreciated.>

Thanks in advance,> Dave>