02 5.3- intermittent sudden jolts and loss of power at high speeds

[SnowDrifter]

Ok, so I've looked into the MAF, but I have never replaced it (i've had the truck for 4 years). @Fless Not sure what the condition is like. @SnowDrifter I've had the fuel pump go out on this vehicle before, and it was a very different loss of power, so I'm pretty confident that that's not it. I'm interested in the water-in-fuel idea, it has been raining a lot where I am at and maybe could've got in there somehow. I'm not sure what Drive by Wire is, @rockola1971 can you explain?

Yeah when mine first started, I thought it was the torque converter. Only happened for a split second. Felt like it was randomly locked and unlocked. Got worse as time went on and I was able to properly diagnose it

 

[rockola1971]

Yeah when mine first started, I thought it was the torque converter. Only happened for a split second. Felt like it was randomly locked and unlocked. Got worse as time went on and I was able to properly diagnose it

Yours couldnt have been the Torque converter unlocking/locking because your vid shows you driving at about 38mph and then slowing down to around 30mph. Torque converter lockup does not happen until right around 45mph so your torque converter wouldnt have been locked up.

 

[rockola1971]

Wasn't 2002 the crossover year where the earlier built ones had drive by cable (DBC), but later in that same model year it was converted to an electronic throttle body (DBW)? Or was it was the '03 MY?

Not sure since the oldest ive ever owned was 2003. Both of my 2003 Tahoe LT's have DBW and of course my 05 Yukon Denali has DBW too.

 

[OR VietVet]

Wasn't 2002 the crossover year where the earlier built ones had drive by cable (DBC), but later in that same model year it was converted to an electronic throttle body (DBW)? Or was it was the '03 MY?

I think I did hear, but never researched it, that the change took place during 2002.

 

[SnowDrifter]

Yours couldnt have been the Torque converter unlocking/locking because your vid shows you driving at about 38mph and then slowing down to around 30mph. Torque converter lockup does not happen until right around 45mph so your torque converter wouldnt have been locked up.

Oh I know
That was the vid I got after I got the problem to manifest predictably. First time it happened, I was on the freeway going ~70. Just a random hiccup for a fraction of a second.


And FWIW, torque converter doesn't fully lock up until like 58 ish. Whenever it can go full-lock at >=1500 engine rpm. Lower than that, and it's in partial lock. PWM nonsense and what have you

 

[rockola1971]

Oh I know
That was the vid I got after I got the problem to manifest predictably. First time it happened, I was on the freeway going ~70. Just a random hiccup for a fraction of a second.


And FWIW, torque converter doesn't fully lock up until like 58 ish. Whenever it can go full-lock at >=1500 engine rpm. Lower than that, and it's in partial lock. PWM nonsense and what have you

The beginning of lockup will happen around 45mph and around that speed you should see a jump in the tach which will appear to be a transmission shift. In fact many people mistake it as a shift thinking they went into 3rd so they miscount shifts and misdiagnose a transmission that is only shifting 2 times when it should be shifting 3 times 1-2-3-4 so its missing 4th(OD).