High Idle

Disconnect the IAC and see if the idle speed drops. If it does not, you have a vacuum leak.

If the idls speed does drop then you have other problems.

Check the TPS settings:
Try this... Currently there is some dispute about setting it at .99 volts being worth the effort, but anything less is probably OK. All you need is less than 1.0 volt at idle and more than 4.25 at Wide Open Throttle (WOT). You'll need a Digital Voltmeter (DVM) to do the job.

The Orange/White wire is the VREF 5 volts from the computer. You use the Dark Green/Lt green wire (TPS signal) and the Black/White wire (TPS ground) to set the TPS

Here’s a TPS tip I got from NoGo50

When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a little in very small increments. I wouldn’t try to adjust it using marks. Set it at .97v-.99v, the closer to .99v the better.

(copied from MustangMax, Glendale AZ)

1. Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.

2. When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.

3. Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery lead for 10 minutes.

4. Check the procedure for your year, on my 90 I have to turn the idle screw until it just touches the tab, then insert a .010 feeler gauge and give it about one more turn. Then you adjust the TPS voltage to .98v, reset the computer. Start it up, if the idle is to low then turn the screw in until it is just right, then readjust the TPS voltage to .98v and reset the computer and start it up. The key is to adjust the TPS voltage and reset the computer whenever the idle screw is changed.

You may want to check the TPS signal voltage w/DVOM to see if the output is higher than 1.2vdc throttle closed. If you washed the engine bay with the engine still warm, it could be possible to have the TPS damaged (thermal shock). Another way to check, would be to run a KOEO self-test....to be sure no other problems exist. LUK

1SLWGT said:

jrichker - joel5.0 - thanks for you input, i will try it later tonight. jrichker - it looks like you have close to the same mods that I have. what does your car run? have you had it dynoed? look at my garage to see my mods.

Click to expand...

No trips to the track yet, but I know that i would be traction limited. No dyno runs either, too much money that I need for other things.