[M.steward77]

Having a problem with the idle. About a month or two ago the van would idle fine until it got warm so it told me the o2 sensor. Because the the van runs completely off of the iac valve(idle air control) until it warms up to 150-170 coolant temp and then the o2 sensor kicks on. But it wouldn't. So I changed the o2 sensor and boom problem fixed! But now I have the completely opposite problem. The van won't idle until it warms up and the o2 sensor is on. I have to force the idle or it will die. So I thought maybe the iac valve is bad, so I ordered a used one from Adam Ford off of the same year van that is a parts van. Put It on, and same problem. Anyone have an ideas? Could both the iac valves be bad? Most things online point towards that, very annoying problem. Thanks so much.

[Cole]

Always hard to tell with a used part.

Anyone near you with a good running van that would let you swap out a "known good part" just for testing?

[M.steward77]

Not that I know of, very very few inline 5 in st Augustine, just met a guy who has one but his runs very poorly so, and I just met him driving by his house. The Bentley manual says to test the iac you should turn the key to on position and feel for a hum, I do feel the hum, and if that passes , ohm it out and it should be between 2-10ohms and both are sitting at 5-6. The weird thing is, if I let the engine sit for maybe 8 hours while I'm at work, and I come back it starts up and idles like if it was warm. I leave for work at 6:00am and never have time to try and start it and feel for the hum. So I'll try that tomorrow morning. 

[trbowgn]

All of the ignition components recently tuned?  I had some random idle issues and did a full ignition tune up (plugs, wires, cap, and rotor) and it smoothed right out. 

[M.steward77]

Yup, changed all the plugs, and wires and stuff around 5-8,000 miles ago. And just recently checked timing, all was good. Thinking about replacing the intake air temp sensor, could not be telling the engine the correct thing and making it run rich.  Does anyone know if the van has a mass air flow sensor, i have heard it does not, and cannot seem to find it anywhere on the intake hoses and lines all the way up to the throttle body.

[M.steward77]

And if anyone here owns a 93 van, if you wouldnt mind pulling your intake air temp sensor off, check to see if the little sensor in the cage is supposed to be loose, you dont even have to take it off, just tap on your temp sensor and see if it makes a rattling noise. Mine does that and i have a weird feeling that is not supposed to be that way.

[lister]

Nope, shouldn't rattle.
I've  had a load of issues with my van recently, rough idle, lacking performance, over fuelling and bogging down. Turned out to be an issue with relays. My ecu relay was working intermittently and my fuel pump relay was only putting 10volts to the pump.

[M.steward77]

Sweet! Thanks for the response I'll get a new iat sensor soon, and so was the solution just get a new relay? Or was it replace the ecu?

[lister]

Just new relays