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

[JohnnyRosso]

So, I recently fixed a handful of things on my truck to fix a misfire problem I was having, and it worked but all of the sudden I have this new concerning problem. Very intermittently (twice in about 2k miles), when driving at fast highway speeds, I will feel a loud jolt in my car and the whole car will move. In both instances, it happened a couple of times and then I started slowly losing power. The second time, it kept jolting at lower speeds until I came to a complete stop. However, in both cases, I just let it rest for a bit, and when I started driving again, no problems whatsoever. It has been three weeks now since the last time with no problems, but I'm thinking of taking a longer road trip this next week and wanted to see if there was anything that I could do to stop this from happening again.

 

[Fless]

What's the history on the MAF? It may need cleaning or replacing, with preferably an OE part. Had a similar issue with an old Ferd Exploder that would buck once in a while.

 

[OR VietVet]

Feel or hear a "loud jolt"? May be MAF and use a Genuine GM part or AC Delco.

More Information for GM GENUINE 19330121

I always do or recommend the MAP at same time:

More Information for ACDELCO 2134434

 

[SnowDrifter]

Can't comment on if this is your issue or not. And might be difficult to test for given how intermittent the issue is.... But I had similar when my fuel pump failed. When the pump got warm, and presumably the fuel as well, output pressure would drop and it couldn't keep up with fuel demand.
Pull over, give it 5-10 minutes, and it was fine for a period of time. Only happened on longer drives - 2+hours where there was enough time to get heat into the system.

 

[rockola1971]

@JohnnyRosso Do you have Drive By Wire?

 

[Fless]

Need more diag. Could be water in the fuel (probably since passed if you drive it enough) or a throttle issue if DBW, as @rockola1971 asked. It would be interesting to see if a code read now or at the time of the problem would show any indicators in the current or history list.

 

[JohnnyRosso]

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?

 

[OR VietVet]

The 02 should be a drive by cable design. I had a DBC on my 02 and now have a DBW on my 05. @JohnnyRosso, a DBW set up is with sensors at the throttle areas as opposed to DBC where you have an accelerator cable for the throttle.

On my DBW set up, I have a throttle pressure sensor on my throttle pedal assembly and have the communicating sensor(s) at the throttle body.

 

[rockola1971]

Changed the fuel filter lately? Ever? Is check engine light coming on during these engine acting a fool events?

 

[Fless]

The 02 should be a drive by cable design. I had a DBC on my 02 and now have a DBW on my 05. @JohnnyRosso, a DBW set up is with sensors at the throttle areas as opposed to DBC where you have an accelerator cable for the throttle.

On my DBW set up, I have a throttle pressure sensor on my throttle pedal assembly and have the communicating sensor(s) at the throttle body.

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?