2000 6.0L runs rough and stumbles
I have a 2000 silverado 6.0 with about 150k. just had the topend off to replace broken manifold bolts no where on cylinders! :metal:
It has been running rough for awhile now. under moderate load it stumbles and has a hesitation. I changed the plugs, fuel pump and filter about a yr ago. as well as the fuel pressure regulator and 2 o2 sen. No codes come up on the scanner so im at my wits end. anyone have simaliar probs? I dont want to have to pay a dealer threw the nose to figure it out. :confused: |
Re: 2000 6.0L runs rough and stumbles
I know you replaced the fuel pump and regulator, but how is your fuel pressure. You might need to find someone (a shop maybe, doesn't have to be the dealer) who has the ability to do some live sensor data logging/scanning to check the operation while running. This may help pinpoint the source of the poor operation. When did you problems start, before or after all of the parts? Did you use AC plugs?
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Re: 2000 6.0L runs rough and stumbles
the problems were before all the parts. some problems went away with the new parts. like hard starting was due to the bad pressure regulator. pump was on its way out and sending unit didnt work so that was a no brainer. I have a local shop that can do a pressure check on the injectors to see if they are working. havent gottin to that yet. they also said try changing plug wires. those are original. the plugs are ac delco. it looks like it runs lean. all plugs are a very light tan almost like they were just put in with little miles and they have about 20k on them. But the shop said that these do usually run lean.
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Re: 2000 6.0L runs rough and stumbles
Harley,
You said the shop recommended wires? Did you change them yet? I have a buddy that changed a lot of the same parts you have turned out to be one of the wires was not putting enough juice to the plug. |
Re: 2000 6.0L runs rough and stumbles
no I havent gotten a chance to go buy a set yet. plan to this w/e after payday. thanks for the info.
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Re: 2000 6.0L runs rough and stumbles
it really sounds like a vacuum leak to me
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Re: 2000 6.0L runs rough and stumbles
Fxdxharley- any updates? I have a 2000 Sierra with a 6.0 and the same problems. I am interested to see if new plug wires help. My motor seems to have a shudder to it and it idles under 500 according to the tach.
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Re: 2000 6.0L runs rough and stumbles
I have a 2000 5.3 with 140k on her! When i put it in gear it stumbles and when i hit the gas it hesitates. It doesn't do it as often on cooler days and runs great above 1,000 rpm I was originally thinking coils but i haven't replaced my plug wires yet!
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Re: 2000 6.0L runs rough and stumbles
have you tryed cleaning the throttle body bore of all the carbon?
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Re: 2000 6.0L runs rough and stumbles
my buddy had a lot of the same issues with his HD. we ended up changing the plugs and wires, and the knock sensors. all better. turns out the plug wires were breaking down and not putting out enough juice. the engine has two knock sensors under the intake plenium. one of which was broke of (looked rusted in two) and while we were in there we changed the other as well for added insurance. not saying thats ur prob. but if you could analize live sensor data, you could see it maybe as stated before
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Re: 2000 6.0L runs rough and stumbles
Never heard of knock sensors what do they do?
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Re: 2000 6.0L runs rough and stumbles
they pick up vibrations and detonation in the block and send that info to the computer to let it know whether to advance or retard the timing to adjust for best overall performance and such depending on set incrimites. thats a pretty basic description. otherwise... they are importand lol
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Re: 2000 6.0L runs rough and stumbles
It would be beneficial to find someone local that can log the truck while driving. I can probably help find a shop that has the equipment to do so that would be willing to help.
But the Knock sensors and the ignition is a good starting point. Also, do you have a K&N style filter? lots of times those are over oiled and the residue gets on the MAF sensor and that messes up things big time. |
Re: 2000 6.0L runs rough and stumbles
Did you change the strainer on the new fuel pump?
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Re: 2000 6.0L runs rough and stumbles
coil packs will go out from time to time, a resistance check i believe will test them...
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Re: 2000 6.0L runs rough and stumbles
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I do need to get over to my local/friends shop and have them run it with the live scanner. money is tight so i just have to deal right now. the truck is like a woman always taken money. :lol: |
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Re: 2000 6.0L runs rough and stumbles
i work on these thing everyday and i have never seena coil go out not say it isn't possible I'd change the plug wires if they haven't been changed. did u use platinum plugs when you changed them i know the newer vehicles use platinum plugs and don't really like anything else. plus plug wires should be changed with the plugs
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Re: 2000 6.0L runs rough and stumbles
well finally got around to replacing the plug wires. she runs a little better but still has the hesitation and little stumble. im thinking its fuel related now. IDK! :banghead: Going to pull the tb and clean it again and check the idle control valve to see if its sticking etc. any other ideas you guys can think of would be great.
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Re: 2000 6.0L runs rough and stumbles
I just figured out mine....I tested the injector harness and was getting the noid light to light up but it was obvisous the cylinder was not firing, header tubes were 'cold'.
ended up having 4 of the 8 injectors not firing, I replaced those not squirting with spare ones and it runs good now. I pulled the fuel rail up and had my son turn the key and watch to see what injectors are firing. and replaced them and run test again. it can be a little mess so you might take a little more time and catch the fuel being squirted out.... |
Re: 2000 6.0L runs rough and stumbles
Im guessing no check engine light? Like posted before the MAF can go bad and not set a light. EGR valve stuck part way open, Vacuum leaks, TPS sensor with a dead spot. If you do have bosch plugs throw them away there junk. Ive always ran NGK V-power plugs there cheap and a good plug never had a problem.
have you checked fuel pressure? Key on engine off 55-62 PSI. |
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Re: 2000 6.0L runs rough and stumbles
bad fuel pressure regulator I've seen it many time on these
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Re: 2000 6.0L runs rough and stumbles
Where is is the regulator on these things? Maybe I should change mine. BTW, when my truck broke a valvespring, the check engine light never came on when I thought for sure it should...
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Re: 2000 6.0L runs rough and stumbles
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Re: 2000 6.0L runs rough and stumbles
that is correct. it is on the drivers side fuel rail. check and see if it is good is by running the truck or cycle the fuel pump with the key, shut it off then up plug the vac line from it. If gas comes out of the port then it is no good. A nother sure way to tell is if your truck starts hard ie cranks over for a little bit before firing up. the pressure reg is a dealer only item and is just over a $100 bucks.
a broken valve sring wouldnt trip the check light. |
Re: 2000 6.0L runs rough and stumbles
i did not think of the valve spring but they are common on these style motors
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Re: 2000 6.0L runs rough and stumbles
I've got the same issues with hesitation and stumbling on my 2000 6.0. The fuel pump took a dive so I've already replaced that. I've put in a throttle position sensor, crank sensor,mass air sensor, and still falls on its face when you try to accelerate. I took it to a shop and had it plugged into a scanner that uses live feeds. It told me that 4 out of the 8 coils were missing under a load. I just ordered a set of 8. This truck has literally broke me lol
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Re: 2000 6.0L runs rough and stumbles
I forgot to mention that I also did a fuel filter and regulator when I did the pump. Also, keep a good eye on the fuel filler neck. Apparently they're known for rotting out and the rust falls down in the tank along with the outside elements. It was a mess!
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Re: 2000 6.0L runs rough and stumbles
Don't pay someone for a live fuel pressure feed. I was a mechanic and all we do is take off the engine cover and connect our mechanical fuel pressure gauge to the shrader valve and drive the thing. save your money.
I'd check pressure first then grab a bottle of brake parts cleaner and a roll of shop rags. Clean the throttle body, pull the egr valve and clean it out. then reach as far as possible into the intake if you don't have cash for injectors pull them out, remove all rubber and soak them in acetone over night You'll be amazed what it'll remove. Oh and when I said a can of brake parts cleaner I mean a case. A lot of problems with new gm motors are traced back to carbon build up and intake gaskets. But I'm new here so don't take my advice as Gospel. |
Re: 2000 6.0L runs rough and stumbles
I'd put money that it's not coils, and if you just bought 8 of em you wasted your money. I have never seen one go bad, not that they can't, but extremely unlikely that 4 went at one time. If you did have 4 dead coils you should be looking at power supply issues before replacing coils. Personally if they told you that it needed coils from just data streams and not actually testing anything, i'd say they are just tryin to suck ya for money and don't really have any idea what they are talkin about. What are the fuel trim readings at? O2 sensors responding properly? Have cats been checked to see if they are coming apart and plugging exhaust? Maf sensor readings and map/baro reading would be helpful as well. Would also check iac as well.
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Re: 2000 6.0L runs rough and stumbles
Come to find out.....I had a couple cooked plugs and a bad spark plug wire. I changed the plugs and got the one wire replaced and this truck runs better than it ever has! The wire was broken internally and it was arcing to the head. This thing is a beast!
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Re: 2000 6.0L runs rough and stumbles
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Re: 2000 6.0L runs rough and stumbles
I would seriously consider looking into the fuel filler neck and the fuel pump. The filler neck was completely rusted out so the rust, water, mud and every other outside element went down inside the gas tank. It was messy and a pain to fix and clean, but what a huge difference! My gas mileage even improved
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Re: 2000 6.0L runs rough and stumbles
good suggestions to look at but not an issue on mine. i changed the pump and filter a few yrs back and just had the bed off to do some body rust repair, filler neck is fine. im thinking a nother bad coil pack. have to bring it back to dealer to be scaned.
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