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Surging During Acceleration

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Old 06-10-2012, 01:28 AM   #1
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Surging During Acceleration

Well, the title says it all. When I accelerate, whether it's standing on it or just driving it normally, my truck, so to say, hesitates when it's building up speed. Let's say I accelerate up to 2,000 RPM. As soon as it hits that and shifts into 2nd, it'll drop a couple hundred RPM's and feel like it's falling on it's face, and then shift into third. There are 105,500 miles on the motor, everything is original. I replaced the fuel filter and I cleaned the EGR valve. It's still doing it. I talked to one of my dad's close friends and he says it might be the catalytic converter itself, that it's plugged. Does that sound about what the problem could be? If so, I'm just taking it off and welding a pipe in its place. I hate them anyways.
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Old 06-10-2012, 01:31 AM   #2
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Re: Surging During Acceleration

As you say everything's original with 105K on the clock, I'd do a proper tune-up. Plugs, wires, cap, rotor.

The if the problem continues....
Old 06-10-2012, 01:32 AM   #3
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Re: Surging During Acceleration

That's what I was going to do, but my dad insists that that's not the problem. I know that you're supposed to replace the plugs and wires and do a tune up for sure at 100,000 miles, and I know it wasn't done prior to me owning it.
Old 06-10-2012, 01:43 AM   #4
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Re: Surging During Acceleration

Quote: Originally Posted by Coyner Jr
That's what I was going to do, but my dad insists that that's not the problem. I know that you're supposed to replace the plugs and wires and do a tune up for sure at 100,000 miles, and I know it wasn't done prior to me owning it.

Methinks herein lies the problem.
Old 06-10-2012, 01:51 AM   #5
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Re: Surging During Acceleration

Alright, thanks! I'll get a date set up in the shop for it and I'll let you know what happens!
Old 06-10-2012, 02:39 AM   #6
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Re: Surging During Acceleration

shop? What for? Lefty loosey Right tighty. Get to work. Took me maybe 10minutes in a gravel driveway. LOL
Old 06-10-2012, 03:53 PM   #7
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Re: Surging During Acceleration

Quote: Originally Posted by JeremyCollins
shop? What for? Lefty loosey Right tighty. Get to work. Took me maybe 10minutes in a gravel driveway. LOL
Exactly what he said, learning to do basic maintenance now will save you lot's of time and money in the future. You have a very easy motor to work on in general and tune up is cake.

If the problem persists after the tune-up, than maybe consider taking it to the shop to have them check your timing and fuel pressure.
Old 06-10-2012, 11:02 PM   #8
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Re: Surging During Acceleration

Unless you're an experienced S10 mechanic, plugs, wires, cap & rotor can be a half day's work. The spark plugs are most easily accessed through the wheel wells with the truck raised off the ground or the wheels removed. Plug #3 will be a bitch.
Old 06-10-2012, 11:06 PM   #9
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Re: Surging During Acceleration

definitely easiest with the truck raised on stands but I had no trouble getting my plugs out. Everyone says its terrible but I guess I just got lucky and was barely able to slip past the steering shaft.
Old 06-12-2012, 12:17 AM   #10
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Re: Surging During Acceleration

Quote: Originally Posted by paul bell
Unless you're an experienced S10 mechanic, plugs, wires, cap & rotor can be a half day's work. The spark plugs are most easily accessed through the wheel wells with the truck raised off the ground or the wheels removed. Plug #3 will be a bitch.
Exactly why I am not doing it myself. I am perfectly able to do it, but I don't have enough time in my day to do it myself, and I don't feel like ripping it apart. I'd rather just let the local small down business do it for me.
Old 06-12-2012, 01:12 AM   #11
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Re: Surging During Acceleration

You can do a lot without getting your hands dirty.

Pull one or two of the easiest plugs, and if they look ok, then put them back in and move on to something else.

Does the truck ever pull strong at WOT, or does it always fall on its face?

Do you have any scanner available?

You can tap into the O2 wire at the ECM under that passenger dash for a reading. At WOT under load it should read .9 volts or it's too lean.
Old 06-12-2012, 08:23 AM   #12
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Re: Surging During Acceleration

Coyner, how old is the fuel filter?
Old 06-13-2012, 12:25 AM   #13
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Re: Surging During Acceleration

Well, today, for the most part, it pulled really good. Other days it seems to miss only upon acceleration, but it's still drive-able. The fuel filter is about two weeks old. I just changed it.
Old 06-13-2012, 12:43 AM   #14
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Re: Surging During Acceleration

Check your timing and fuel pressure. If you go to a shop, i personally would only charge half hour labor for something that easy, around 40$. Anything more would be pretty questionable.
Old 06-18-2012, 01:52 AM   #15
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Re: Surging During Acceleration

I got quoted $300 to do the plugs, wires, cap and rotor.
Old 06-18-2012, 03:23 AM   #16
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Re: Surging During Acceleration

Well it may very well need plugs etc., but it also may need much more.

What I would do for my customer after hearing your problem, I would pull one or 2 plugs, the easiest ones, just for a quick peek. Unless they were worn down to the nubs or severely fouled I would not replace them at that time. I would advise my customer that i recommend that they be replaced but I want to do further checks.

I would then get a scanner and a fuel pressure gauge on it and take it for a drive. I would be watching fuel pressure under load, must stay above 60 psi under WOT. I would watch the scanner for fuel trims and O2 voltage. O2 voltage must stay at .9 volts at WOT under load.

That would tell me if you are experiencing a fuel delivery problem. Only after confirming fuel delivery would I go further. I would expect a shop to charge no more than an hour to do these simple tests. Here shops charge $80-120 an hour.

If these checks found nothing exceptional, I would remove the front O2 sensor to check for a plugged cat. This is easy for you to do if the sensor is not seized. 7/8" wrench, you don't even need to unplug the sensor wire, just let it twist and tie it up to drive it. It will be loud. To reinstall twist the sensor wire about 4 turns and install, the wire will unwind as you tighten the sensor. If the sensor is too tight for you just leave it to the shop.

I have seen so many shops do a $300 tune up and then tell the customer they need to also replace the fuel pump, another $500. Sure it might need a tune up, but I would at least give the customer a chance to catch their breath after paying for an expensive fuel pump, and I'd see them next payday for a tune up.

The plugs would need to be in really bad shape to produce a problem you are describing. A good tech can usually tell just by driving if it's a fuel delivery or ignition problem.

Just going by what you are describing my spidey sense tells me you are lacking fuel, but don't go replacing expensive parts until you can prove they are bad.
Old 06-19-2012, 02:30 AM   #17
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Re: Surging During Acceleration

See, the reason I don't think it's a fuel problem is because I still get decent fuel economy, I mean Christ, I got over 20 going 75 MPH when I went downstate the other day.. And I know that's pretty decent for that truck, but I don't know. My godfather has those sensors and I'll probably have him check it out before we do anything major.
Old 06-21-2012, 02:33 AM   #18
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Re: Surging During Acceleration

Quote: Originally Posted by Coyner Jr
See, the reason I don't think it's a fuel problem is because I still get decent fuel economy,
If the fuel ump is weak it can run lean because with less fuel pressure the injectors inject less fuel, and that means it would use less fuel.
Old 06-22-2012, 02:34 PM   #19
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Re: Surging During Acceleration

this sounds very similar to an issue that im having, please keep us updated as to what you find out. do you have any cold start issues?
Old 06-25-2012, 02:32 AM   #20
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Re: Surging During Acceleration

I have no cold start issues, starts every time.

I did learn a couple of interesting facts about this particular motor, which actually make sense. If my fuel pump was even somewhat close to not being perfectly perfect, it wouldn't start at all in the cold. It would just turn over and over and over and over.

The other thing I learned is that when Chevrolet was making this motor in the late 90's, they basically made it so that it "surges" when it's in overdrive. They did this to save fuel, because, for whatever reason, we needed to save fuel in the 90's. While it's in overdrive, the computer basically tells the transfer case to go into lock up, and that's what causes the surging. If I downshifted into 3rd gear and accelerated, it would prevent the transfer case from locking up and it wouldn't surge. Most full size trucks have those towing buttons on them, and those prevent the transfer case from locking up like mine does. So, shifting mine into 3rd does the same thing as a tow button would do. And this does make sense to me because it only surges occasionally. Most of the time, but sometimes it runs like a million bucks. A few years back, my dad had a 2000 ZR2 Chevrolet and he said his does the same thing mine did. Trucks with my engine and transmission with a year close to mine all do this, as a fuel conserving thing like I said earlier. And if I were to unplug the transfer case sensor to make it never surge again, it would apparently wreck my fuel mileage..

So as for what's being done to my truck... it is getting plugs, wires, cap, rotor and a PCV valve, and then I'll get it back. My godfather (who's during the work) doubts that will clear the surging, but I suppose we'll just have to wait and find out!
Old 06-26-2012, 01:56 AM   #21
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Re: Surging During Acceleration

Got it back today, runs great, and it still occasionally surges, but like I said above, it's supposed to do it. I might try unplugging my torque convertor sensor and see how bad it wrecks my fuel mileage, but I'm undecided yet.
Old 07-03-2012, 08:46 PM   #22
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Re: Surging During Acceleration

My 01 4.3 was surging while driving but i was also losing power on hills.Cut cat converter off and replaced with straight pipe.Trucks runs great now.No surging.
Old 07-04-2012, 12:53 AM   #23
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Re: Surging During Acceleration

I think that's what I am going to end up doing to mine.
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