I posted on the Van forum, and got no responses, so I'll try here.
I've got a '90 E150, 4.9l auto. I parked it for around 3 weeks. It ran good at that time.
I went and tried to start it a couple weeks ago, and wouldn't start without using ether. I had to keep my foot on it to keep it from stalling. The check engine light was on until warmed up, then idled normally. I disconnected the MAP and engine stumbled, then idled normally.
The Throttle position sensor has been replaced.
The Air Intake Valve works,
The coolant temp sensor is good.
Battery is new.
I've hooked my code reader up, and the only code I got was 77, WOT not detected/operator error. That was with KOER test. I'm a bit leery on that code, tried it twice with the same results.

Someone mentioned an air temp sensor on the throttle body, well I can't find it.
What else should I be looking at? The MAP? The EGR? The ECM? Sure is strange when you park a running vehicle for a 3 weeks, then it won't start.

 

The on board diagnostics werent that great then. Not untill the mid 90's when obdII came out, and was more user friendly.
Is is possible that something maybe chewed a vacuum line making it run like that? If it was a sensor of some type, I'd maybe think more like a IAC (Idle Air Control).
Hope this is some help.
Unk Bob

 

Idle Air Control is what I meant, yepper, that works good. I took it out and cleaned it, and checked it to make sure it was working. I do live in the middle of the woods, but no on the vacuum lines, no evidence of chewing.
Thanks for the reply!

 

hopefully you didn't have anything get pulled through the air intake or there could be water in your gas now that gas has 10% ethanol CH3CH2OH or C2H5OH
(i am going to look through my chiltons truck and van it isn't the same year put they didn't change very much)

 

Great!! Thankyou!!

 

i think its one of three distributor, a coil, a resistor, after i thought a bit i remembered it happened once with our 85carb i wasn't very old then mine is a 96and fuel injected (it is not the thermostat or carborator) i am not a mechanic but there isn't very many things it could be it should be idling around 550rpm

 

I guess I should have mentioned I have spark, so that should rule out the ignition. I have fuel pressure, the hose jumps when the pump starts.
I just tried to start it using ether, hard to believe this, but nothing.
I've got a 1/4 tank of fresh 93 octane.

 

You got a code 77 because you didn't move the throttle to wide open when the code reader called for it. Do another read and give it wide open when
it asks for it and you'll prolly get an all clear.

Next step for me would be to do a wiggle test to check for a bad connections. Don't buy a bunch of parts until you have each part tested- Autozone can do it for you.

 

It could be a misadjusted TPS, but if someone tries to manually adjust the idle on engines of this era it will produce similar issues. There is a procedure to set the throttle properly using feeler gauges.

 

No, no one has diddled with the throttle plate. I did take the TPS off again, and ever so slightly turned the guts as if the throttle would be at a minimum setting while cranking, still no go.
Out of desperation, I went out and bought new plugs his morning, but haven't put them in. Anyone know the gap I should have? Thanks.

 

I've given up! $300 to first responder. 3speed auto is good, as well as rear end. Selling for same price I can junk it for. Please pm if interested. I'm in Northeast lower Michigan. TIA

 

Don't give up! I'm sure its nothing major, just a bit more time and effort. Did it hit at all when you sprayed ether in it? Have you installed the new plugs? I know how frustrating it can be trying to trace down an issue like this...

 

When all this started, it would start with ether, now it won't. Yepper, changed the plugs. Someone said something about the Thick Film Ignition module on the side of the distributor. He said to take a hairdryer/heatgun to it and the distributor. Sometimes the module gets moisture in there and heating it up will dry it out. That didn't work either. I do have spark and fuel.

 

spark and fuel?should run. check to see if the distributor is loose, and may be turned out of running range. gas could also be real bad, and fouling out your plugs. try some fresh gas.

 

Thanks for trying to help guys, but I've given up. I have too many things going on to use anymore time on this. I prefer just to be done with it. Thanks again.