[Greasedlightning66]

I need some help I have a 2020 SS 1LE M6 lt2, stainless power lth with hiflows, oiled rotofab and a patg flex tune. Setup is about a year and a half old and it’s been running great but recently I’ve been having a small problem. When I’m driving around I’m about to come to a stop and I put the car and neutral the rpm’s stay at about 1000-1500 until I come to a complete stop. On some occasions it’s even stayed at 1500 rpm’s when I’m at a complete stop. I took the intake tube off and looked inside the throttle body and it looked very clean and I also washed and reoiled my come filter.. Im going to spray some throttle body cleaner in it to see if it helps but has anyone else ran into this problem or know what else I can check?

[ctrlz]

Since this is your first post, I would check out the threads here on headers melting portions of the wiring harness.
Your problem may be unrelated, but you want to make sure your wires are properly secured away from the heat.

[Germansheperd1]

Originally Posted by Greasedlightning66

I need some help I have a 2020 SS 1LE M6 lt2, stainless power lth with hiflows, oiled rotofab and a patg flex tune. Setup is about a year and a half old and it’s been running great but recently I’ve been having a small problem. When I’m driving around I’m about to come to a stop and I put the car and neutral the rpm’s stay at about 1000-1500 until I come to a complete stop. On some occasions it’s even stayed at 1500 rpm’s when I’m at a complete stop. I took the intake tube off and looked inside the throttle body and it looked very clean and I also washed and reoiled my come filter.. Im going to spray some throttle body cleaner in it to see if it helps but has anyone else ran into this problem or know what else I can check?

Clean your MAF with MAF cleaner not the TB.

[Megahurtz]

What throttle body are you using?

[Greasedlightning66]

Originally Posted by Megahurtz

What throttle body are you using?

Stock throttle body

[Greasedlightning66]

Originally Posted by Germansheperd1

Clean your MAF with MAF cleaner not the TB.

I’ll try that out!

[Greasedlightning66]

Originally Posted by ctrlz

Since this is your first post, I would check out the threads here on headers melting portions of the wiring harness.
Your problem may be unrelated, but you want to make sure your wires are properly secured away from the heat.

I checked from under the hood and it didn’t like like any wires were touching the headers but I’ll check under the car too.

[Kmeleon]

Do you have Rev match turned on? I noticed my revs will hang similar to what you describe but if I turn it off it stops doing it. Never noticed it before my tune.

[Hostile_1LE]

Originally Posted by Greasedlightning66

I need some help I have a 2020 SS 1LE M6 lt2, stainless power lth with hiflows, oiled rotofab and a patg flex tune. Setup is about a year and a half old and it’s been running great but recently I’ve been having a small problem. When I’m driving around I’m about to come to a stop and I put the car and neutral the rpm’s stay at about 1000-1500 until I come to a complete stop. On some occasions it’s even stayed at 1500 rpm’s when I’m at a complete stop. I took the intake tube off and looked inside the throttle body and it looked very clean and I also washed and reoiled my come filter.. Im going to spray some throttle body cleaner in it to see if it helps but has anyone else ran into this problem or know what else I can check?

I had an issue like this after a 5 hour drive. I thought it was something messed up in my tune… it was actually just that one of the clamps holding the cold air intake to the throttle body had come loose, letting air past the MAF. I think typically that high idle while rolling only is gonna be cause by un-metered air entering the engine.

[Greasedlightning66]

Originally Posted by Kmeleon

Do you have Rev match turned on? I noticed my revs will hang similar to what you describe but if I turn it off it stops doing it. Never noticed it before my tune.

No it’s off when this is happening.

[Greasedlightning66]

Originally Posted by Hostile_1LE

I had an issue like this after a 5 hour drive. I thought it was something messed up in my tune… it was actually just that one of the clamps holding the cold air intake to the throttle body had come loose, letting air past the MAF. I think typically that high idle while rolling only is gonna be cause by un-metered air entering the engine.

I checked for some vacuum leaks and I took my tube out to check out my throttle body but I’ll tighten each of these clamps down just to be sure

[SSDan]

Originally Posted by Greasedlightning66

I checked for some vacuum leaks and I took my tube out to check out my throttle body but I’ll tighten each of these clamps down just to be sure

I had a similar issue and it turned out to be a vacuum leak from my oil catch can. The can drain valve was accidently left open after I drained it and it caused a big vacuum leak. Good luck! Chasing down weird problems like this can be very frustrating.

[KingLT1]

Sounds like a vacuum leak that you simply haven't found. Need to data log and see what the fuel trims look like.

[Ventmaster]

A "hanging fast idle" is nearly always an intake side air leak. Besides clamps, etc... be sure to check the torque on your LT2 IM- don't over tighten! Specs should be in inch/pounds. Not very tight at all. If you are unsure or don't have a good inch/pound torque wrench, take it to someone who does.
It should be an easy fix, but you can do more harm than good if you're unprepared.