I have a 2004 Buick LeSabre with 200,000 miles and no codes. . I have loaded up the parts cannon and I am stumped. The engine will intermittently stall. You can be going 70 MPH down the highway or idling and the engine it will just stall.No codes and it runs fine until it stalls.
Here is what I've replaced:
Upper and lower intake gaskets - there was a lot of coolant on top of the engine so we started here.
Fuel pump
Fuel pressure regulator
Ignition switch
Mass airflow sensor
The coils and spark plugs were changed about 20,000 miles ago.
There is no indication that it will stall like running rough or no power.
Engine? Transmission?
Check the crank position sensor and throttle body.
When you say "no codes" do you mean the car was scanned with a generic OBD2 code reader, or was it a pro-level scan tool like the one Scotty uses? (Dealer tool would be a Tech2.) Any live data?
Crank sensors frequently exhibit a failure mode where they fail when hot and then start working again when they cool down. However it could be a lot of things and more data would be helpful in analyzing the problem.
It is an OBD2 reader that Scotty had recommended. https://www.amazon.com/gp/product/B073GW5MTS/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
It can gather sensor data but I'm clueless on what would be useful data.
Its a 3800 V6 with an auto transmission.
What, if anything, does the data show when the engines stalls?
I'll hook it up and see what I can capture. I appreciate your attention to this. Stay tuned.
Look for anything in the recorded data that goes funny in the head at the point where the engine stalls.
I spent some time running it but was unable to recreate the problem. Of the data I saw, it is subtracting -25 on the long term fuel trim.