BACK FIRE

[JD Diesel]

In the morning when I leave for work getting on freeway it sounds like it back firing truck jumps a little bit and keeps going. Seems like it only does this in the mornings. The free way is a bout 1 1/2 miles from my house. Any Ideas we are bone stock. JD :confused:

[More Power]

I'd change the fuel filter as a first step in troubleshooting most engine running problems. Secondarily, fuel in the tank will contract overnight as the temperature falls. This can produce a vacuum in the fuel tank. If there's a cap vent problem, the vacuum can reach a point of starving the engine for fuel. Try loosening the cap before that first start in the morning, as a step in troubleshooting.

Check for codes.

Jim

[royalglen]

Thought I was the only one with "Back-fire" problems.The truck is an 05 D/A with 7000mi.We just come from a 2000mi trip with 10000lb 5th wheel on behind.My first thought was that the transmission was still thinking and not back to no-load mode but it is lasting longer than it should.The back-fire occures only during shift. Any advice.

[JD Diesel]

about same milage as you and just got back from a trip with my trailer. it only does it once in a while in the morning. JD :eek:

[rjschoolcraft]

You guys might be hitting the rev limiter. JD mentioned "getting on the highway"... If your matting the thing through shift points, that's probably it and it is an adaptive learn thing with the transmission.

[JD Diesel]

No not matting it just gettin normal its a real long on ramp. no need for quick speed. JD

[01max]

g.m knows about a backfire problem they are working on a fix for it.this is on a 05 lly only

[JD Diesel]

O1max are you tech that you know about this problem. JD

[01max]

yes i am a g.m tech, we have a truck that we have looked at for this problem it happens under hard accel throttle above 70-80% mostly 2to3 upshifts sometimes 3to4 there is a pi bulliton about this

[madmatt]

Sweet...good to know as we've sold a ton of 05's and I've yet to see this.