P0171 and the Dreaded High Idle After TB Cleanign
2010 LT autotragic with about 110,000 miles under her.
I have had P0171 pop on and off for the past 21/2 years of owning this magnificent turd, but I felt I needed to mention the code as well.
So backstory. Had a buddy who services all my cars do an oil change and TB cleaning. He hosed the TB down with TB cleaner like it was a protester in the streets, then poked a soft microfiber cloth in and out to get the crap out of the hole.
Yes, he moved the butterfly valve manually with one finger. Engine was off, Battery was still hooked up.
After putting all the hoses and intake back on, it took a bit of coaxing for the engine to stay idling by itself. Now when it did, it ran fine and actually alot smoother now the TB doesn't have, well, TB. Now here comes my dumb self in the driver seat about 5 minutes of the car idling. I get out of the car and hit the accelerator with my big toe while stepping out. The car screams to 3,000 RPM and refuses to come back down. We turn it off, check for vacuum leaks and the sort, nothing is found. After coaxing the pos back to life again the idle stays nominal, 800rpm or so. Put it in gear, let off the brake, the idle will jump to around 1200rpm and the car will "accelerate" up to a coasting speed of 20, where the idle thinks it's okay to be.
After a week of doing drive cycles both city and freeway driving, the car is a bit better, the idle doesn't always go to 3,000rpm, but now to a more less butt clenching 2,000. I also have this awesome little problem in which I am accelerating and the car will lose power from 2,000-2,400rpm. It doesn't always do it but it feels more like a twitch if that makes sense. We have tried the relearn procedure, unhooking the battery, and a completely different intake. I am at my wits end and now thanks to the extra strain on the brakes, I got those to do again, which were replaced 3 months ago.
I do not have access to a gm scan tool, and I am really hoping to not buy a new TB as even the local scum junkyards want $150 for one. Any and all information will help. I know this is thread #40,931 about this issue, but it seems someone else has it slightly different and their fix isn't working.