hesitation at highway speeds...
 

Guys ive just got my truck running again, and let me tell you it is so nice to have it back. I do have a problem that has plagued the truck since i got it. While cruising at 65-75 down the highway, it feels like it hesitates occasionally. There is no noise, and no other indicator that it is going to do it, but there is definately something causing it. Do any of you guys have any ideas?

The truck just both heads redone, and new gaskets from there up.
new plugs
new fuel filter
new drive belt

There might be other things, but i dont remember them all.

tia for everyone's help

-Michael

RE: hesitation at highway speeds...
 

Dont know if this is exactly what youre experiencing but I had a problem with torque converter shudder. Feels like youre running over the little reflector bumps. Always happens at highway speeds, usually uphill. Converter locks and unlocks really fast. I patched mine up with a tube of "Dr Tranny's Instant Shudder Fixx." Its a thick red fluid similar to transmission fluid that goes in your trans fill.

RE: hesitation at highway speeds...
 

really? where did you get it?

RE: hesitation at highway speeds...
 

Oughta be able to find it at Auto-Zone or O'reilly's. I got mine at O'reilly.

RE: hesitation at highway speeds...
 

Every once in awhile I have this same hickup (as I call it). Turning off my A/C makes it less noticable, but still there. I have verified with my scan tool that it is not a lockup issue, but still have not found a cure...

RE: hesitation at highway speeds...
 

i have the same problem with my 2001 trailblazer, goes away when i turn the a/c off. only at highway speeds

RE: hesitation at highway speeds...
 

I want you all to go out and test your TPS.








My a/c was acting real goofy, and my truck would run real high rpms at times while ideling or starting out, especially on hot days.
you guessed it, it was my TPS.

RE: hesitation at highway speeds...
 

I have a few ideas, but no solid answers. Most of the checks are impossible without a scanner than could take a "snapshot"
Check the control module grounds for being clean and tight.
Could be a fluctuation in fuel pressure (weak pump or restriction in fuel filter.
TCC
Intermittent egr problem
Crank position sensor
Along with all the usual things like corrosion on the dist cap terminals, or cap and rotor, plug wires, vacuum hose leaks.

Not to bad to look for loose ground wires and leaking hoses or corrosion, but for all the rest, espescially intermittents, it's almost impossible without a scan tool.

RE: hesitation at highway speeds...
 

I noticed mine would do a very slight hickup for the first ten minutes of driving in the mornings. Barely noticeable...not jerky or anything, if you didn't know what to wait for, you wouldn't feel it. but now it doesn't seem to be doing it anymore. maybe it had something to do with the gas.

RE: hesitation at highway speeds...
 

how do you test the tps?