there's a lot going on here and I'm trying to follow. Can you just disconnect the wideband and run the car? If it's tuned ok and not relying on closed loop AFR control, it doesn't need a wideband hooked up for a temporary test (start, idle, drive around the block without boost).

 

Pretty easy to test though. I had mine stuck above that when I was adjusting the frequency. Unplugged it from the valve and idle dropped instantly to the point of stalling. That could be combined with a slightly mal adjusted throttle stop.

The other thing is the car using the factory wiring harness? If so, how old is it? Wondering if either it's got a crack or two causing a slight short or noise in the signal ground. Even a bad crimp or some sketchy joins. I'd remove any extra grounds that have been added, check the ECU ground and then disconnect all sensors but one to see if the noise is reduced. If it isn't you're probably going to have to look at the harness.

 

Update: She lives!!

I want to thank each and every one of you for responded. I read your responses over and over again, and every once of them contributed to the fix (and contributing to me fixing this idle surge) and the car runs now. So let me do a quick recap and the current situation.

After wrestling with the issue and not being able to figure it out, I got in contact with Mr. Chris Ludwig and we got straight to work. We looked over a few things, tried recalibrating the TPS (fail), ran some continuity test on the TPS signal wire (pass), swapped the wires out and reassigned them to verify they weren't broken (all good), then we made a breakthrough. My TPS jumper harness was wired incorrectly...I could not make this up.

So on the Haltech sensor that I purchased, the jumper harness (short harness that connects the actual engine harness to the sensor) had the signal wires backwards...but it wasn't clear at first. What led to that is when Chris had me disconnect my Haltech TPS and connect my stock TPS, I was able to calibrate the TPS (by hand of course). So I thanked Chris a 1000x, hung up the phone and got to work taking off the throttle body. Took it off, took off the Haltech TPS, and while simultaneously walking toward the door to my kitchen and putting the stock TPS on the TB...the door hits me square in my forehead. My girlfriend hit me so hard with the door that I threw my hands over my head and completely forgot about the TB and TPS. Well I dropped them, with the TPS being held on by one screw....annnnddd it broke. Great.

SO to wrap this up, I got frustrated with my Haltech TPS and decided to run a continuity check on the jumper harness. Oddly enough, the last 2 wires were backwards from one another. So I swapped them around, made sure to mount the Haltech TPS before I left the kitchen, walked it to my car with both hands on the TB, put it all together, calibrated the TPS, and just like that....the car started!

I have had some weird problems occur in the midst of all of this. My stock dash died, but when I swapped from my AEM WBO2 gauge to the Haltech WBO2 controller....it came back on. And currently, I'm working on the idle. And its no fun at all. I need to just make the switch to DBW because the TB is ancient technology that just doesn't make a lot of sense in 2021.

 

That's the hardest problems to find - one where you assume something that SHOULD be good is good.

Hope you are driving the streets soon!

Dale

 

Thanks Dale. And you're absolutely right/ Without Chris and Seth, it would've taken me years to figure out the TPS was the issue AFTER I had just replaced it. Just goes to show I have to do my part in checking over everything I buy...both new AND old...before installing on the car.

Once again everyone I'd like to thank you all for your help. I always try to pass forward the help you all provide for me forward so I can do my part in keeping these cars on the road.