slow dropping idle

[sabotahj]

could it be IAC going out? I know after i put that restrictor plate doohickey on mine, it acted kinda funny for a while during the relearn procedure. Hung at 2 grand, then dropped to 1500 and hung there for a few seconds, then dropped to like 400 and caught itself before it died. You may want to check that out.

[94 cobra]

How about following the advice in the thread first before you go throwing another motor in it or trying to hack job a way around the problem. Auto ECU's aren't the same as the manual ECU's.

i have done 3 5 speed to auto swaps and never had any problems with the ECM doing this now it was on 2 91's and a 86 but never had any problems. it dosent act like the ECM. if it was it would do it all the time. right?

[94 cobra]

could it be IAC going out? I know after i put that restrictor plate doohickey on mine, it acted kinda funny for a while during the relearn procedure. Hung at 2 grand, then dropped to 1500 and hung there for a few seconds, then dropped to like 400 and caught itself before it died. You may want to check that out.

i turned the adjuster screw all the way in. i was told it would bypass it.????
it also cuts out at high rpm like its running out of fuel. but that might be something else. it seams like a vac, leak but i have sprayed carb cleaner around everything and no idle change

[Vertnut]

The '94/'95 computers, and the Fox-body computers are not the same. The '94/'95's can be finicky, to say the least.

[Diabolic]

Look, make a block-off plate out of an aluminum can. Then bolt the IAC back on. Disconnect the spout for the dizzy and set to 12º. Drive it up to 30mph. Does the idle still fall slow? If yes then you have a vacume leak, if no, then plug back in the spout. Does the idle hang now? Yes, it's timing related, no it's IAC related. Get a new IAC from FORD, and I cant stress that part enough, or get a tune to raise the decay rate.

[94 cobra]

Look, make a block-off plate out of an aluminum can. Then bolt the IAC back on. Disconnect the spout for the dizzy and set to 12º. Drive it up to 30mph. Does the idle still fall slow? If yes then you have a vacume leak, if no, then plug back in the spout. Does the idle hang now? Yes, it's timing related, no it's IAC related. Get a new IAC from FORD, and I cant stress that part enough, or get a tune to raise the decay rate.

Ok. Thanks I will try that as soon as I get back in town and I'm taking
It needs to be completely blocked off?

[Diabolic]

If you want peace of mind. Block it off and unplug it! Ha ha ha! No seruiously.

[94 cobra]

If you want peace of mind. Block it off and unplug it! Ha ha ha! No seruiously.

i still want it to work. i just spent 600 bucks to get the a/c working right. dont want to have have it idling at 1000 to stay running with the a/c on. the IAC still rasies the idle up with the a/c on

[TENGRAM]

the IAC still rasies the idle up with the a/c on

It also keeps the engine from stalling when rolling up to a stop... reason why the VSS, gear switch, and clutch switch are so important.

[94 cobra]

well the only thing i have left is the ECU. im going to replace it next weekend i sure hope thats it

[Diabolic]

i still want it to work. i just spent 600 bucks to get the a/c working right. dont want to have have it idling at 1000 to stay running with the a/c on. the IAC still rasies the idle up with the a/c on

I suggested steps to isolate and then correct the problem. If you don't do what I said then you can just keep on chasing your tail. Do what I mentioned. Isolate the problem, then address the problem. My gut feeling is that you will need to modify the dashpot decay rate in the tune as well as changing the mph at which the car begins to run off the "idle" parameters. I have a 95 Cobra with a fairly aggressive camshaft. The idle would start to fall quickly but then hang about 1500. Gradually it would settle to 1200 rpm. Once I stopped completely it would settle down to 750-800 rpm. I did all the things I mentioned above only to find out that the problem needed correcting in the tune. I also added 100 when the AC clutch kicked on. You need to tune the car.