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Chevy Silverado and GMC Sierra Gasoline Engine Problems



  • 1998lincoln1998lincoln Posts: 108
    You never told me what type of automobile you have ! One thing to look at , the
    heat sensor is telling the motor it's still cold and needs to inject more fuel !
    This happens with silverado's sometimes ! Just something to look at ! Good Luck !
  • ms1378ms1378 Posts: 7
    Thanks for replying, will take a look at that..bythe way I own a 2001 2500 6.0 vortec..gas sucking beast that it is, got it when gas was not so much of concern, but it still pulls any trailer that i hook to it w/ out problems.
  • obyoneobyone Posts: 8,054
    I'd be more concerned if the oil pressure didn't move in relation to rpms. What you describe as occurring would be the correct operation of the gauge.
  • eliaselias Posts: 2,120
    rj, yes it should still run if you unplug the O2 sensor after the cat.
    it seems likely that your truck's catalytic converter is clogged.
  • I had to change the lower intake gasket a couple days ago, had a bad leak all of a sudden. This was by far the dirtiest motor I have ever been into. There was at least 3/8 to 1/2 inch of sludge on the hold down plate for the lifters and a 1/4" at least of build up with sludge on top on the floor of the valley. It only has 87k on it! I have a 73' impala with 84k on it and that looked like new compared to this. Well, I got it all back together and so far it has not died yet. I'm not going to hold my breath though cause last time I thought it stopped dying I was wrong. I'm keeping my fingers crossed. If it dies again I'll unhook that O2 sensor and see what happens. Thanks for the input.
  • well, no go, brother drive it to work and almost didn't get back home. Died half dozen times or so, along with popping and banging and backfiring. Would be happy to roll it off a cliff !!!
  • obyoneobyone Posts: 8,054
    Yep sludge is never good.
  • i think its time to replace the comp that will cause all the problems that you have mentioned and especially if u have replaced all the items you've listed
  • i have a 94 silveraldo that i just replaced the plugs and wires in and done them 1 by 1 now the truck is running worse than it did b4 i replaced them it spits and sputters like i got a plug wire off but there isnt and has a big loss in power but it dont cut off does any1 have any ideas and also done a tranny service the motor has a skip in it and i have a few ideas but just wanted to see if anyone has had a similar problem
  • 1998lincoln1998lincoln Posts: 108
    edited April 2010
    When Stalling , here are some things to look for ! Good Luck

    To test the exhaust, remove a spark plug, hook up a compression tester, crank over engine, when it starts, if the compression is high, cat. converter is stopped up and has to be replaced !
    the engine temperature sensor! It was failing so it was telling the throttle positioning sensor that the motor was cold so it kept dumping allot if fuel. So when the gas was pushed it flooded it and it would die!
    the low idle was a common problem on these engines. Actually, the real problem is that the accelerator is sticking (although this is not as evident as the low idle; this is why you feel the surge, instead of a smooth acceleration. The low idle is a by-product of this problem). The problem is due to hydrocarbon (sludge) buildup inside the throttle body, and possibly the air flow sensor. clean both (I assume with something like common carb cleaner?).
  • 1999 GMC Silverado 5.7L 67,000 miles. HIGH OIL PRESSURE
    The engine oil pressure is too high, on start up the pressure gauge pegs past 80 PSI. The oil filter o-ring blew out. I changed the oil and filter 10W30 and it blew
    the o-ring out again so I tightened the heck out of it and am able to start in now.
    The oil pressure is still maxed on the gauge, after warm up at idle it will drop to about 50PSI but if engine RPM is increased it goes past 80PSI.
    Any sugestions on what might cause this? Is it possible that the relief valve is stuck? Where is the relief in the pump? Does the oil pan need to come off?
    Can it be removed without pulling the engine? Thanks for any help!
  • wolvestxwolvestx Posts: 1
    I am looking at purchasing a 2001 Chevy 2500HD Crew Cab 6.0 2WD. Before doing so I am trying to find to the average fuel economy. I currently own a 2005 Toyota Tundra SR5 Crew Max with a 4.7. The gas mileage is horrible at 14 Cty/Hwy combined. Any help would be appreciated.
  • obyoneobyone Posts: 8,054
    You won't find EPA mileage numbers due to it being a 2500 series truck. However, if my memory serves me correctly I think you'll average 10 mpg loaded and 12 mpg unloaded.
  • I got it all straightened out, ended up being the fuel pressure regulator. Sure threw me off the way it was acting, wish it would have done the hickupping $400 sooner. I would have started with the regulator instead. But hey, on the plus side, it has alot of new parts that i shouldn't have to worry about for quite some time. thanks for all help
  • ms1378ms1378 Posts: 7
    I have a 2001 2500 crew 4x4 , trailer or no trailer, loaded or empty I get 10 mph..maybe 11 with the wind at my back
  • did you replace the sensors or fix the wiring or both? i have the same problem on my 04 silverado with the 5.3 engine.
  • solocamsolocam Posts: 3
    My truck sounds like a Diesel when I start it up. It seems to take longer for it to go away. Any ideas? I only have 56,000 miles on it. I have tried the oil filter with check valve, Lucas oil stabalizer. I am scared it is getting worse. Please Help......
  • hvychev77hvychev77 Posts: 3
    hard to find until you get a "check engine" light on....Did u try the crankshaft sensor or the coil packs?
  • redi_jediredi_jedi Posts: 9
    kinda sounds like the oil pump is starting up dry, or or maybe weak. if the oil pump don't get the oil flowing right away, it can produce the sounds you are hearing. i would think the miles are low enough that it shouldn't be a problem with bearings, but worn out crankshaft bearings will make that sound too. does it go away once it is warmed up? i would check the oil pressure before i do anything. maybe even check the oil filter, if it is clogged up it would prevent the oil pump from getting the necessary flow, which would result in the diesel noise on start up. once the oil gets hot and can flow easier, it might lessen the noise. Just a few thoughts. Good luck
  • redi_jediredi_jedi Posts: 9
    try the fuel pressure regulator
  • dtsddtsd Posts: 1
    My 1994 GMC Sierra 1500 4x4 has all of a sudden decided to not idle without dying. My son was pulling out from a driveway and it started to idle and try to die. He has changed fuel filter twice in 3 days, plugs, wires, fuel pump, O2 sensor. Nothing has seemed to help. It will almost always die when idling, no matter how long the engine has been running, and sometimes dies when slowing down to turn a corner. Any more ideas except a mechanic. Thanks in advance.
  • obyoneobyone Posts: 8,054
    Idle air controller.
  • redi_jediredi_jedi Posts: 9
    does it die at random? then start back up? I have a 99' chevy k1500 and that's what it did. ran fine but died at any given time at any temp., I spent $400 on various parts. plugs, wires, coil, dist. cap, rotor, O2 sensor, map sensor, crank sensor, fuel pump relay, fuel filter. then one day it hiccupped real hard a few times. so i changed the fuel pressure regulator and so far so good, seemed to have solved the problem. does your idle fluctuate up and down? if so i would say throttle position sensor. if not, MAF sensor maybe. a vacuum leak some where could cause similar symptoms. good luck, sorry for rambling
  • 1998lincoln1998lincoln Posts: 108
    edited May 2010
    the engine temperature sensor! It will fail, so it will tell the throttle positioning sensor that the motor was cold so it kept dumping allot of fuel. So when the gas was pushed it flooded it and it would die! Problem solved!!
    Let us know if this helps you, These autos are having this problem !
  • pete114pete114 Posts: 2
    I have a 2000 Silverado 4.3 v6 I had problems last year with intermittent stalling then, it completely died. The mech replaced the fuel pump....ran fine for 10 months now it went back to intermittent stalling then it died again, mech replaced crankshaft timing sensor, rotor cap and the actual rotor i think.
    It died two miles from garage on the way home...back to mech he said it was a loose battery cable not giving enough spark to plugs.
    It ran great for 2 days back to intermittent stalling.
    it does it while idling or running at highway speeds it seems like it stumbles a little.

    Any help please?
  • pete114pete114 Posts: 2
    I cleaned out the throttle body which helped a little.
    The next day it wouldnt start...I found that the rotor was somewhat corroded so i cleaned it.
    It fired up but we noticed that the spark from the coil seemed weak, so I replaced that.
    This morning it idled fine so On the road it missed a little until it died completely.
    Now I have no spark whatsoever from the coil and the ignition module tests fine.

  • tom467tom467 Posts: 1
    Hi I have researched the forum and worked on this problem but there seems to be so many possibilities I'm hoping someone can narrow it down. My GMC seirra (2001) with a 4.3 V6 has developed the following problem over the last week. At first there was a very slight surging when driving at steady state throttle. This has now become a massive surging that resembles applying and removing half throttle at 2 second intervals while the throttle is actually held steady at half throttle. The interval between the engine running fine and having no power at all is very repetitive and continues no matter what speed. I have removed and cleaned the cap and rotor, checked plug wires and the TPS. I have changed the fuel filter. The p0300 code is set when driving under hard acceleration and massive surging. It seems to me that the ignition is turning on and off. When" on" all cylinders are firing, when "off" no cylinders are firing. Any suggestions would be very appreciated.
  • redi_jediredi_jedi Posts: 9
    my 99' k1500 with a 5.7 died at random, i replaced just about every sensor under the hood. cap and rotor, plugs and wires, coil, ignition module, map sensor, crank sensor, still nothing. one day it started doing what you are describing, i replaced the fuel pressure regulator and it hasn't done it since. I dont know if that is your problem but it would be worth checking in to.
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