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Check Engine Light/Reduced Power/Service ESC issue

Grit dog

Nov 9, 2021
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Sorry if this is close to K10guy's thread, but doesn't look like this site is overloaded, lol.
'20 TB 5.3 10 speed, has had both banks of lifters done in the last 5k miles or so, under 30k on it still.
Few nights ago, drove it 300 miles home, no problem.
Morning, remote start it, and truck died/didn't stay running.
To start, it took 2 long cranks (5+ seconds of cranking).
Before ever putting it into gear, ck engine light, service ESC and Engine power reduced comes up.
Try to drive it, it's a turd, won't get over 40mph. Making similar whining noise as lifters, but whatever.
Have it towed in.
Now here's where it get weird.
This afternoon, I'm told that it ran fine for tow truck driver, ran fine at dealer, no codes, no check engine light. Dealer took it for a rip up the local mountain pass and back down, never a hiccup.


Said they're going to run it again with diagnostics going or something. Suspect maybe bad ECM?

Gettin pretty tired of the Trail Lemon! LOL

Anyone else have same or similar issue? K10guy hasn't posted up the solution to his yet.
I have a 21 LT with 6.2.... almost 17 K and runs perfect..... always use Mobil 1 oil and premo gas... been to the end of the Baja and back from PNW ... heading down again in april... best mileage 27 mpg ... it see's full throttle once a day... tranny temp never goes above 147 ... knock on wood no issues... gas prices now are scary as my commute is averaging 14 mpg ....
Grit Dog, sorry brother for no updates. Been working and hot rodding these damn rental cars around town lol. My TB has been in the shop since Feb 21, 2022.

Issues started around 800 miles. Never had a no crank. When TB goes into limp mode, I am able to go around 60mph but with high RPMs, I stayed around 45-50mph straight to the dealership.
1st Shop: Feb 21 - Apr 4 2022: Replaced speed sensor, pass throu Harness, and some valve...guessing body control valve. Issues seemed to be resolved. Drove it 300 miles and issues re-appeared.
2nd Shop: Apr 14 2022 - TBD: Service Tech stated transmission is the issue. They are running more tests to see if bad parts can be replaced or if it needs a new transmission.

Not gonna lie, TRX was my first choice but the thought of owning a $80-90K truck with know history of transmission/rear-end issues, I went with the TB. Plus I have a 85 K10 and a 97 Silverado C1500. A TrailBoss would look great with the collection. Just have to keep it out of the shop.

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