New driving issue reared it's head

[doctor al]

2005 trailblazer inline 6. Sometimes while driving it, it will shake and shut off but then fires right back up. Changed the coil packs but that didn't cure the problem. Been to 2 techs and still now answer. Any ideas? I'm going to go ahead and replace the fuel filter and air filter again, but, I'm stumped.

 

[TollKeeper]

Any pending, or current check engine lights? What are the codes?

 

[c good]

Check your grounds. I had a bad ground connection on my PCM that was intermittent. It would do the same thing but would also blow a fuse sometimes. Not always....that's why it was so difficult to diagnose.

 

[doctor al]

Any pending, or current check engine lights? What are the codes?

No check eng lights and according to GM tech, no codes. I'm baffled.

 

[doctor al]

Check your grounds. I had a bad ground connection on my PCM that was intermittent. It would do the same thing but would also blow a fuse sometimes. Not always....that's why it was so difficult to diagnose.

Thank you... will check the ground.

 

[budwich]

change your fuel pump relay.

 

[doctor al]

change your fuel pump relay.

Would a defective relay throw a code?

 

[budwich]

There is no codes for that as there is no checks / sensors in the system.

 

[c good]

change your fuel pump relay.

I agree. Try this first. Good call Budwich.

 

[TequilaWarrior]

Does the shaking/stalling occur after a fuel fill-up? (Especially from empty to full.)
On my wife's car (a Ford Escape for complete disclosure), every time we willed up from empty to full, it would shake/shudder/stall 1 time within a day or so of filling up. Then not do it again until we filled up again from empty to full. I ended up replacing the EVAP canister and the EVAP purge solenoid twice before the problem went away altogether.

 

[doctor al]

Does the shaking/stalling occur after a fuel fill-up? (Especially from empty to full.)
On my wife's car (a Ford Escape for complete disclosure), every time we willed up from empty to full, it would shake/shudder/stall 1 time within a day or so of filling up. Then not do it again until we filled up again from empty to full. I ended up replacing the EVAP canister and the EVAP purge solenoid twice before the problem went away altogether.

No, there's no set pattern... just all of a sudden it'll shudder and shut off. Always starts right back up.

 

[Mooseman]

Another possibility is a flaky ignition switch that will lose contact when heated by increased resistance. I'd throw a new one in there just to eliminate that possibility, along with a bad ground.

Also, have a look at this thread where a similar issue arose from a broken trace in the fuse box. Certainly worth a look:

SOLVED! - long crank after engine suddenly stops

This car runs very well otherwise but recently on two occasions suddenly stops running many lights flash on the dash along with the CEL. Numerous codes set dealing with emissions like PO443,P1516,P1682,P2101,PO443 then cranks but will not start. Occasionally, it will start after stopping upon...

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