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Chevy Silverado and GMC Sierra Gasoline Engine Problems



  • If the noise is coming from the belt friction. A simple test is to spray water on the belt while it is running. If the problem is belt friction, the noise will stop immediately!

  • helomekhelomek Posts: 4
    1999 4.3l 2wd reg cab short bed,

    At about 70-75 mph I feel hesitaion, like there's not enough gas, ignition bad, or transmission. It idles fine, has get up and go from a stop. Already replaced the fuel pump a while back. As I did with the spark plugs a few months ago, and just replaced the fuel filter, I just had to change my catalitic converters, at 105,000. I do have a lot of miles, but my truck has been good to me and I want to keep it a while.. I have done everything I know. I want some input before I take it in....
  • helomekhelomek Posts: 4
    1999 4.3L 2wd reg cab, short bed

    I have a bad vibration at highway speeds. I already changed shocks, Bilstein, rotated tires. It's bad when I hit the brakes, BUT, I already changed the pads and rotors. Dealer already looked at it once and said everything was "good". Does anyone have any ideas, before I take it in.... Please Help...
  • catamcatam Posts: 331
    Has anyone out there had to replace the knock sensor on the 5.3L.
    I talked with a guy I know who stated it is under the intake manifold.
    I am happy to do this job myself, but I am just wondering if anyone out ther has personal experience with removing the intakes on the 5.3, and any helpful hints before I start the job.
  • obyoneobyone Posts: 8,054
    Have you changed your tires? I would hope so being that its a '99. Did the vibration begin before or after the current tires were installed?
  • jeffrey3jeffrey3 Posts: 2
    my truck knocks when i start it for about 2 minutes everytime

  • obyoneobyone Posts: 8,054
    Ever heard of piston slap?
  • helomekhelomek Posts: 4
    I have changed my tires. Bridgestone dueler. I would say after, I am not sure.
  • obyoneobyone Posts: 8,054
    Seeing that you changed your tires, shocks, pads and rotor, there is one last option if you qualify for it.

    In model years '99 and '00 there is a TSB out for vibrations. It is not well known and only affects 2WD trucks with the rack and pinion. The reason I know about this is that I had my rack changed under warranty with the new rack and no vibration problems. The vibrations usually started around 40-45 and lasted till about 65-70. If this is what you are experiencing, I can post the TSB for you to take to the dealer. Course being out of warranty it will not be free or cheap to do.
  • I have the same problem with my 99. Mine does it when I let off the throtle and get back on it. I think it is a transmition problem. Like you, if I step on it, it goes away. What I usually do is manually shift down a gear(automatic tranny) and the shutter goes away. We also tow a large travel trailer with ours. I've just gotten used to down shifting.....the tranny is too expensive to open up.
    Good luck
  • Hi nelsonsrick,
    I took the truck to the dealer. I had 1 TOTALLY fouled spark plug and 2 CRACKED plugs!!!! They also replace the wires. That did the trick. A week later, I traded in for a new 2007 3/4 ton Silverado. Have someone check your plugs and wires. I had 69,000 miles at the time.
  • bunnbunn Posts: 2
    Been told that GM's answer is that no oil is stored in the filter when engine is shut off. Therefore upon startup oil has to be redistributed and noise stops.
  • obyoneobyone Posts: 8,054
    Who at GM told you this?

    It is a bunch of BS. If you ever changed your own oil, you will be able to disprove that theory. The oil filter is full of oil when changing unless GM has found a way to change the laws of physics and gravity.
  • jimseversjimsevers Posts: 22
    I agree, this is a BS excuse from a dealer who is trying to give an explanation for a common symptom of these motors. People don't want to hear "it's a common symptom that will not lead to any permanent damage, rather it is an annoyance". This may be true, but nevertheless, it was a design flaw that GM did fix in the next gen V8's. There is no "fix" for it other than to minimize it by using synthetic oil and putting up with it for a minute or less upon cold starts. I have not heard of any cases where this lead to any real mechanical issues or engine failure. Anyone else?
  • obyoneobyone Posts: 8,054
    True haven't heard of any engine failures. I would think it would affect resale. From what I've heard its more prevalent on the 6.0.
  • Don't use common carb cleaner!!!! Use Mass Air Flow Sensor cleaner by CRC. Spray into sensor and let dry. It dries quick. Don't rub or scrape the sensor
  • Clean the MAF sensor first and see if that doesn't do the trick. Also folks, those after market oiled air filters ( k&n, etc) can gunk the MAF sensor, causing problems, if you over oil the filter after cleaning it
  • I was just about to tell you to check your plugs!!
    I had a tranny service, and the guy told me it was an ignition problem. So today I did the wires and plugs....problem solved too!!
    I also changed my fuel filter....I have 314,000 km
    thanks anyway
  • aik262aik262 Posts: 9
    it,s a blot on bypass tube, for engines that don't have oil cooler option,it just my be loose
  • eyoumanseyoumans Posts: 2
    I have a '99 GMC Sierra with 229,000 miles. I want to swap the 4.8ltr. to a 5.3 ltr. Can anyone tell me if all connectors will interchange between these engines? The cable harness look to be the same. How about the computer?
  • iv got a 2000 5.3. cats went bad, and replaced them, throwing codes, like maf sensor, o2 sensors egr, sensors, replaced them all. put new plugs and wires, still wont run right. checked voltages in o2 sensors(11.5-12.5 volts) checked MAF voltage(8.5-9.5) normal? dont know. keeps trowing code 174 = system too lean (bank 2). cant figure out why it will not run. PLEASE help if any body knows whats goin om here. idles ok slow acceleration will rev out, only in neutral, put in gear to drive under a load, the motor falls on its face, seems like starving for fuel. also changed the fuel filter, still nothing. any help is welcome, thanks.
  • lionslions Posts: 20
    Ok i have a 2002 5.3v8 ext a cab 4x4 with 42,000 never been hurt or abused just driven lately my truck has been using 2 qts between oil changes every 3000 miles my dealer says this is normal 1 qt per 1500 miles ?? I checked my owners manual and no where does it say this is normal so if any GM techs are reading what do you think also the knock in my engine is getting worse even after the engine is warm. I hope GM is watching Toyota because what i seen of the tundra is wow but i haven't driven it yet. But am a long time GM chevy truck owner but i think 2qts inbetween oil changes is excessive, with the new technolgy and tighter engines they weren't suppose to burn oil. So any help would be great. Thank You Lions
  • 1offroader1offroader Posts: 208
    lions - you're right, 2 qts./3,000 mi is too much. I'd say any more than 1 qt./3,000 mi. is excessive. The knocking is worrisome, but may or may not be related to the oil usage. Are you sure the oil is not dripping anywhere? If not, check the compression on all 8 cylinders. That's a point to begin diagnosing both problems.

  • jmj2000jmj2000 Posts: 1
  • obyoneobyone Posts: 8,054
    Park it in the garage and drive a prius. ;)
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