So I recently picked up a somewhat beat up 98 Base Lude 5sp for $2500 with 151k miles and as expected, I have some issues. I've been looking around to find answers, but so far, nothing helps. So, at the risk of being flamed, I made my own topic.

1. When I got it, it had the 'surging idle' that the guy told me would be fixed if I got an Idle Control Valve. Grabbed one from Autozone, and it still does it. To describe the idle:
Starts up then jumps to around 1200 RPMs and then pulses up to around 2000 and drops to 1200 then repeats. Consistently.

2. There is a whine with the engine that doesn't seem like it's the CAI, but I could be wrong. With the idle issue AND the whine, I sound like such a bastard at stop lights

3. This could have to do with the idle issue, but while driving at around 60-65 in 5th gear, my RPMs are at around 3000-4000. Now, I know this can't be normal if the Mustang I just got rid of was less than that in 5th at 90 with 4.10 gears...

4. CEL: P0117 ECT Sensor... Is this easy to do myself/will it fix the idle issue? This is the only code I'm throwing.

5. Found a few random unplugged wires looking around. Can someone help identify them for me? I have pictures:






****If necessary, I can take a video of the idle issue/engine whine.

 

does it only do the problem when cold?if so, the idle issue could be your Fast Idle Air Valve. its on the the bottom side of the throttle body. there are plenty of write ups around here to delete it. you can either replace it or bypass it by connecting the two coolant lines and blocking off the ports on the FIAV. another idle issue is cause by the EGR ports.

my prelude is runs about that high in 5th gear and at that speed.

 

as for the other problems, i would replace the ECT sensor.. that also could cause you to have a weird idle.

 

Nah, it does it warm and cold. And I'll see if I can find a writeup for replacing the ECT sensor.

 

Took it to a shop to check it out, and apparently there's a short in the wire running from the sensor to the ecu and it's making the ecu think the engine is at max temp and has the idle all screwed up -_____- and I may possibly need a new ECU after I get the short fixed.