4.2l trailblazer shutting off while driving

[sphinxbccp]

As I.V said, check and clean mass airflow... My blazer was doing that (not dieing tho) i cleaned the mass airflow and it runs great now, even if it looks clean it might not be.

[dblovah51]

aite thanks guys will let yal know the solution when its fixed.

[Ben Fultz]

you could also try checking your TPS ( throttle position sensor) They can get a worn or flat spot since they spend 75% of there time in the idle position.

[kickass audio]

I had the same thing but it was a problem with the firmware revision I had flashed for the PCM and ECU. I had all the computers in my truck reprogrammed and flashed to the current revisions and have had 0 problems. The throttle response is way better, the truck shifts better, I only on rare occasions have a little bit of a wait before the truck responds when flooring it and my problem of the truck stalling or choking out is no longer existant. Mine had a lot of things replaced before I updated the computer. For example I had the EGR valve, throttle body, smog pump, spark plugs and fan clutch. Even after all of those were replaced it still was very sluggish and the engine died 3 times and a 4th time it was about to die but recovered. At the time of the software update I had also had my water pump replaced. After updating everything seems perfect. I really think its software related as it acts like the engine is being choked off from the air/fuel mixture. I know other people mentioned but check your MAF sensor. Im 99% sure your TB has one, the envoy's dont. For the 2 total times mine had been "choked" off the engine rpm would drop down to about 200 or 150 and you would see the voltage drop, oil pressure starting to drop (isnt the real oil pressure anyways, FU GM lol), and then I felt a slight shudder, almost like if you were driving in a manual transmission vehicle and shifted incorrectly between gears and then it went back to normal idling at 750rpm and ran fine. The other times I had no notice of it stalling, it never shuddered, made noise or had any of the dummy lights on which was odd because at minimum the check engine, check gauges and battery dummy lights should have illuminated.

The software update is pretty costly and though I did get a discount since im a good customer of my mechanics shop it cost $300 for just the software updates.