Stalling

[Saint_La_Ron]

I have 2008 denali 6.2...It starts up fine but when you either slow down or come to a stop it stalls out. I've changed the crankshaft & 2 of the 02 sensors that came up on the scanner yet it does the samething. After 2 start ups the stabilizer light comes on the truck will drive without stalling but the rpm on the dash doesn't move. Anybody else ever encounter this issue?

 

[Fless]

What codes "came up on the scanner?"

When was the throttle body last cleaned, and is it clean now?

Test the IAC function. Any vacuum leaks?

When you say you changed the crankshaft I'm going to assume that you mean the crankshaft position sensor. After changing it, a CASE relearn should be done with a capable scanner.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

These trucks are very sensitive to electrical connection and ground issues. I would first check all grounds in the engine bay, particularly the braided ground wire from the engine block to the firewall. Then, check the ground on the frame underneath the truck, approximately below the driver's seat.

What do you show for fuel pressure, as the engine starts to fail?

 

[Saint_La_Ron]

What codes "came up on the scanner?"

When was the throttle body last cleaned, and is it clean now?

Test the IAC function. Any vacuum leaks?

When you say you changed the crankshaft I'm going to assume that you mean the crankshaft position sensor. After changing it, a CASE relearn should be done with a capable scanner.

I did the relearn after changing the sensor....The code that are coming up are P0336, P0335, P0420 & P0175