You right this thing has vacuum leak written all over it. I've checked out all my vacuum lines and have squirted carb cleaner in every nook and cranny......nothing! Well I was driving it earlier and now I'm getting an intermitant CEL and it does act like it's running a little lean. I'll pull the codes again and also check out my MAP sensor.........THANKS

 

Be sure to post your results ! - good luck !

 

Do the KOER tests, too.

 

I'm still scratching my head over this one!

Here's a quick recap of what I've replaced, IACS, TPS, Engine Coolant Temp sensor and an Air Charge Temp sensor, not to mention plugs, wires, cap, rotor, fuel and air filter plus plenty of injector cleaner.
I wasn't showing any fault codes but didn't see the harm in replacing some of my 12 year old sensors. I also did some checking with a voltage meter and couldn't find anything out of specs.
The truck still wanted to die at start up and wanted to stall until warm.
I got home yesterday afternoon and just parked the truck in the driveway. Around 11:00 pm I went out and started it, same old thing it wanted to die. After a few minutes of nursing the throttle I got it to stay running and hold an idle around 650. Here is were the story gets weird!
I disconnected the vacuum from the MAP, the idle jumped to 1500 and held. I plugged it back in and it dropped to 700 and held. I unplugged the Map sensor, it went to 1500, plugged it in, back to 700. I turned the truck off unplugged the MAP, truck wouldn't start, plugged it in, the truck started.
I then unplugged the IACS, the truck wanted to die but didn't, finally I guess the PCM went into default mode and the idle picked back up to around 700. I then proceeded to plug the IACS back in while running and it instantly killed the truck. I'm thinking well that's great all I need to do is screw up my EEC. I made sure the truck would again start and went to bed.
This morning the truck started perfect, idled up just like it should, then down, just like it was supposed to and I never touched the throttle.
This afternoon after sitting all day, the same thing, it started and ran perfect!

My question is what happened? Did I reset somthing in the EEC by sending it into default mode and then back? Do I have a MAP sensor acting up? Could the new IACS be faulty?
I told you this was weird, but the truck seems to be fixed!

 

WHo knows what happened -mine has a mind of it's own most of the time .
I'll bet the map sensor was at fault .
Still no trouble codes?-

 

yeah my truck fixed itself too! The front gas guage works now for some reason.

Well its good to hear its working.. hopefully it will stay like that.

It must have zapped some sense into the computer somehow. Maybe a sensor was reading wrong and simply "rebooting" fixed the problem.

 

When I checked my KOER codes I got a "system pass" when I checked my KOEO I came up with RPM's unable to reach upper limit and RPM's unable to reach lower limit. I could have told you that by watching my tach and the way it was starting. Well it's seems to be running good for now but I still think I might change out the MAP sensor this weekend (might as well I've replaced about everything else) clear my codes and check it again.

 

5-8-03
Truck again not wanting to start and now it has a bad miss.

5-9-03
Replaced Map and O2 sensor (why not I've changed everything else, read above posts)
Cleared computer, truck still runs bad and now it's showing an unable to reach high rpms, unable to reach low rpms and an HEGO sytem running lean codes.

5-12-03
I GIVE UP

5-13-03
I take my truck to the Ford dealer. A few hours and around a $100 fuel injection cleaning later my truck runs like new. ( gas additive fuel injector cleaners just don't do it)

5-15-03
I'm still driving around with A SMILE on my face

I HOPE THIS HELPS SOMEBODY!!!!!!