Cant go over 75-80, shakes like a bastard..

[jaybone]

The truck is a 1999 Tahoe 2WD Police Package with 175,000....

Had trans rebuilt at 130,000ish... and had some diff work at around the same time....

Problem is....
When approching 65 i get a vibration in the floor and a humming noise... then if i try to acclerate through it i can get the truck to about 75-78... And thats it... This truck hasent seen over 80mph in years... I remember it used to be able to do 110-120 with no problem... It was like driving a camaro not a tahoe...

I use it as my "around the town" truck. I dont usually take it on the highway.. So it drives perfectly normal and quiet at speeds under 55mph...

I found the fuel filter was pretty clogged and replaced it.. No Change..

I can go WOT until 55mph and the truck spins the tires and goes with no prob..

Any ideas...

 

[bowtiefreak]

wheel balance is where I would start

 

[jaybone]

wheel balance is where I would start

Did the balance..
replaced the wheel bearings as well....

I am swaying towards something mechanical because i cannont drive through it.. the truck hesitates so bad i cannot achieve speeds over 80...

My car had a balance problem.. But i could drive it over 100+ with the wobble...

 

[DenaliAK]

Yeah, doesn't sound like a simple balance problem. Unfortunately, I can't think of any "good" scenarios for the symptoms, either. Clean everything...injectors, MAF, plugs...and see if it helps.

 

[jaybone]

Yeah, doesn't sound like a simple balance problem. Unfortunately, I can't think of any "good" scenarios for the symptoms, either. Clean everything...injectors, MAF, plugs...and see if it helps.

So your thinking a fuel issue? I did find the clogged fuel filter, that i changed... I think a bad MAF would give me a CK Engine light... And i did the plugs inside of 30,000 miles ago (but i'll check them)..

 

[rucr8z2]

So your thinking a fuel issue? I did find the clogged fuel filter, that i changed... I think a bad MAF would give me a CK Engine light... And i did the plugs inside of 30,000 miles ago (but i'll check them)..

a MAF sensor can fail in range and not set a ck light

 

[jaybone]

a MAF sensor can fail in range and not set a ck light

ok good point... but would it limit the speed of the truck...

I hope the Z56 Police Package MAF is the same as the regular one...

 

[TIM Z]

Just another thought, maybe you have a restriction in your exhaust some where? Cats ??

Just sounds like somethings holding you back?

Could be ignition coli also petering out on higher RPM's ??

 

[jaybone]

Strange.....

Today, a few days after i did the fuel filter.. I realized the belt tensioner was bad... I popped a new one on with a new belt.... It felt a little stronger....

I got it on the parkway and went WOT.... It hesitated for a moment and then woke up and took off like a rocket....

I dont know what the tensioner would do to fix this?? All i can think of is that there was something in the fuel line that was restricting the flow, and when i nailed the gas it must of unclogged itself???

So now as i was approching 100mph i was running out of gear? Which led me to a issue that was in the back of my mind......

A year ago a mechanic "fixed" my rear diff.. I usually work on my own truck, but i was out of state and had no way to do it.... It seems to me that in fixing my rear, somehow.... My 3.08 rear went missing and now i have a 3.73 ring set!

Anyone have a 3.08 laying around? lol... Never ends....

I included a picture of my baby.. =)

 

[blackcoffee]

My truck has a 3.73 gear set and with the with my setup and my tune I can go well over 100mph easily.
*Which I would never advise doing on mud tires btw*