I have a 2004 4wd 4 door with 81,000 miles. Just had all 4 wheels balanced and now I've noticed a vibration idling and also going down the road from zero up to 70-75. It feels like electricity running through the truck. I feel it on the floor, gas pedal, steering wheel and also the seat..... PLEASE HELP!!! THANK YOU......

 

If I properly understand your Blazer does this vibration from complete standstill until high-speed.
Therefore I'm at this time ruling out: Drive-shafts, axles, wheel bearings, wheels and suspension.

For an analysis you may do the following: (take a flashlight along.)

I have tried to come up with a little analytic chain.
It's kind of a very basic troubleshooting I do on cars and trucks with similar problems.
Follow each step and take note what you find.
At which point does the vibration cease, change or get worse?

Preliminary check, possibly with engine cold and definitively switched OFF:
- Engine shut-off. Have a look at the radiator fan. Is it missing a blade or has a distorted damaged blade/s?
- Check the v-belt visually for cracking, wear, damage, are the ribs smooth and no small pieces amiss?
- Check all the components, tensioner, idler pulleys by wiggling them. (CAUTION not to pinch your fingers)

Possibly when engine is cold:
- Keep the truck parked, transmission in P and park brake set. Start the engine.
- Switch A/C to OFF. (this will make the compressor pulley disengage)
- Switch OFF the HVAC in order for the fan to stop (could be the culprit - worn fan)
- Rise the rpm by 500 - 1000 rpm. Does the vibration change with engine rpm?
- Does the engine shake as if it is not running on all 6 cylinders?

In idle go have a look at the front of the engine (CAUTION moving parts, look, don't touch):
- Again if possible with a flashlight, check the v-belts routing. (does the belt flutter around at some point?)
- See if one of the pulleys wiggles (not running round).
- Do you "hear" anything resembling the vibration?
- Go for a test-ride and warm the Blazer up to operating temperature. (Anything changed)

Found anything?

So much for "free" preliminary checks.

 

I replaced the fan clutch. Still vibrates!! Checked everything else out you recommended also.
Any other suggestions please!!!

 

It's not by throwing parts at it that a problem get's solved.

Still an open question (see my "assumption")

Is it vibrating at "standstill" or when driving?

 

Hi Guy's..... Here's my update. Here's what I've replaced in the past few months. Complete GM parts tune up, Belt tensioner and pulley. Intake manifold gasket, Front and rear U-joints, harmonic balancer and I'm still getting a vibration even at an idle to 70+ mph......????? Anyone have any suggestions?? PLEASE!!!!!

 

Ist it vibrating at standstill. Does the vibration change at any time (i.e. the faster you go does the vibration change with an increase in speed).

 

Hello.....Thank you for your reply!!
Yes the vibration intensifies as you gain speed. From a dead stop idle to 70-75mph.
Feel it more in the floor then the steering wheel.

 

Maybe a stupid question, but You said you just had a wheels balanced, so let's stick to the wheels:
- do You have the lugs tighten properly? Aren't they loose?
- a chance of huge mud chunks on the inner side?

Additionally, are the vibrations related to a vehicle speed or to the engine rpms? I feel a bit confused, as You say the vibrations are also on idle.

If they're rpm dependent, I'll check:

• cylinder misfire
• motor mounts
• fuel pressure (in case of a random misfire)

As for the V-belt accessories, You may grab the pulley, remove the v-belt completely and try out. You'd be out of steering pump, alternator and most important out of a coolant pump, so make it as quick as possible.

If they're vehicle speed dependent, not rpm, I'd check:

• u-joints and shaft balance (improper mount?). That is a very important step.
• cv boots condition
• jack up front, check for any abnormal sounds or loose components...

Enough for the moment I guess