Rough running

1997 CHEVROLET SILVERADO
140,000 MILES • 5.7L • V8 • 2WD • AUTOMATIC
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JEREMY400
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So I got this truck about 6 months ago from the original owner. Everything on it is stock he didn't change anything. I did have to change plugs, wires, cap, rotor, and ignition coil. It ran just fine after those repairs. About 3 weeks ago I took it to work and I noticed that it started having a little hesitation like a misfire but it wasn't bad and the only code was for bank 1 sensor 2. But there is a little exhaust leak next to the sensor. So I drove it a few times after I noticed the hesitation/misfire again and it seemed to come and go. Well yesterday I took it to work again and something went. It runs pretty bad. When you give it gas it shakes. So I wanted to check for a possibly a bad plug. So I started it and pulled each plug wire off at a time and put back on and down the row. There wasn't any change in how the engine ran when I did that. It cant be driven right now. I was thinking maybe the distributor is on its way out? I don't want to start throwing parts at it. I am trying to properly find the problem. There is also a small odor of gas but not strong. I'm not sure if that's just cause the engine is running rough or what. It does fire up just fine though. Just runs really bad. Appreciate any advise.
Sep 13, 2021 at 2:11 PM
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DANNY L
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Hello, I'm Danny.

What it sounds like you are experiencing is an issue with the "spider" injection. This is the fuel injection tubes mounted in between the upper and lower intake manifold. This is a common problem in these Vortec engine. I had the same issue in my 1997 K1500. I've owned a 1997 and 1989 K1500 so I know these trucks well. It would be a good idea to stick with the Delphi or AC Delco replacement as I've heard some people having problems with fitment-issue on cheaper brand replacement. Here is a tutorial showing how to replace an intake manifold:

https://www.2carpros.com/articles/replace-intake-manifold-gasket

I've attached picture steps below on how to replace the "spider" injection on your Chevrolet truck. I've circled the part in red. Pictured are my 2 below as well. Let us know if you have any further questions on this issue. Hope this helps and thanks for using 2CarPros.
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Sep 13, 2021 at 11:50 PM
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JEREMY400
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Would this by chance cause my plugs that I replaced not to long ago to look like there going bad? The cap which I also replaced has crusty stuff on the electrodes. Overheating?
Sep 14, 2021 at 11:05 AM
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DANNY L
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Hello again.

Yes, it would cause new plugs to foul immediately and cause a slight misfire and slight hesitation on acceleration. The junk on the cap is it bad and how badly overheating? Hope this helps and thanks again for using 2CarPros.

Danny-
Sep 14, 2021 at 1:16 PM
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JEREMY400
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The white crap is on all of the electrodes and when accelerating everything shakes pretty bad.
Sep 14, 2021 at 1:37 PM
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DANNY L
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Hello again.

How long ago was the distributor cap replaced? All signs however point to the "spider" injection problem I've mentioned in my prior post. Hope this helps and thanks again for using 2CarPros.

Danny-
Sep 15, 2021 at 3:30 AM
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JEREMY400
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So I did put a new spider in there. One of the fuel injectors was not working. Now I can't get the damn Injector ports to lock in the engine. I'm not trying to break them from force. I did try a little oil on them to slide in and still didn't work. Any ideas? Thanks.
Sep 19, 2021 at 1:58 AM
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ASEMASTER6371
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I would clean out the port before trying to instal the injector.

Can you upload a picture of the one you have trouble with?

Roy
Sep 21, 2021 at 4:41 AM
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JEREMY400
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I cleaned all the ports. When I said one injector was bad I meant on the old unit. So on all of the new injectors the plastic part slides in the port just fine until it gets to the metal part of the injector. I tried pushing a little more but they won’t move. They do get snug but I can pull them out without pushing that one tab on the side. Should these be locking in place when I push them in?
Sep 21, 2021 at 7:37 AM
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JEREMY400
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Here is the picture:
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Sep 21, 2021 at 7:39 AM
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ASEMASTER6371
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What is that a picture of? It is not of any injector.

Roy
Sep 21, 2021 at 10:43 AM
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JEREMY400
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I’ll have to get a better picture tomorrow. That’s a spider injector. The rest is in the hole. I just wanted to know if it has to click in or not. Or if it looks fine. When I took the old ones out I had to push a tab an pull them out. This is on a 1996 Chevrolet Silverado 5.7L vortec .
Sep 21, 2021 at 11:01 AM
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ASEMASTER6371
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They must go in and click to be sure they are seated. If you do not seat them, they can back out.

Roy
Sep 21, 2021 at 11:03 AM
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JEREMY400
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That’s what the injector looks like. I just took it out. The black plastic part goes in fine up to the metal part. Then it won’t go in any further.
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Sep 21, 2021 at 11:10 AM
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JEREMY400
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Okay.
Sep 21, 2021 at 11:10 AM
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ASEMASTER6371
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Is the black plastic part of the old spider or the new one?

Roy
Sep 21, 2021 at 11:15 AM
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JEREMY400
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New one.
Sep 21, 2021 at 11:23 AM
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ASEMASTER6371
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Are there holes on the bottom for fuel to come out of? I wonder if they are protectors for the injector when boxed and shipped.

Roy
Sep 21, 2021 at 11:28 AM
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JEREMY400
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There are holes for the fuel. I was just doing a little research on these. There is a video on YouTube of a guy named “Klowny”. He does this same job an he says just to push the plastic all the way in until it hits the metal part of the injector. He has a video on it. Not sure if you want to check that out. I just don’t want them to flop out an have to rip that intake off again.
Sep 21, 2021 at 1:26 PM
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ASEMASTER6371
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I would assemble it but I have never had that issue prior to seeing this.

Roy
Sep 21, 2021 at 6:59 PM
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JEREMY400
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Okay. Appreciate the help.
Sep 21, 2021 at 8:32 PM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Let us know if you have any other questions.

Roy
Sep 21, 2021 at 8:36 PM
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JEREMY400
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So, I assembled it all and my misfire is gone but now it sounds like the carb is whistling. idles really rough. Carburetor gasket? I did spray carburetor cleaner around and nothing changed. But when I took the air cleaner off and sprayed around the carburetor. It idled high then shut off. I put the cleaner assembly back on and started it and it fired up but ran rough.
Sep 25, 2021 at 10:51 AM
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ASEMASTER6371
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If you put your hand over the top of the carburetor with it running, does the whistle stop?

If it does, you need to either rebuild the carburetor or replace it.

Roy
Sep 26, 2021 at 6:16 AM
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JEREMY400
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I will have to check when I get home. I meant to say throttle body not carburetor.
Sep 26, 2021 at 6:50 AM
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ASEMASTER6371
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Okay, check that and see.

Let me know how you make out.

Roy
Sep 26, 2021 at 7:18 AM
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JEREMY400
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So, it did not shut off it sucked my hand onto it. It doesn’t sound like it’s whistling anymore. Here is a video of what it sounds like:
Sep 26, 2021 at 7:58 AM
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JEREMY400
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Video.
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Sep 26, 2021 at 7:59 AM
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ASEMASTER6371
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I don't like the way it sounds. It sounds like it has a misfire.

Did you check the compression? I would start there. You need 140-160 pounds in each cylinder.

https://www.2carpros.com/articles/how-to-test-engine-compression

https://www.2carpros.com/articles/symptoms-of-low-compression

Roy
Sep 26, 2021 at 8:08 AM
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JEREMY400
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All cylinders read around 159 PSI and I did a fuel pressure test also and it was at 60.
Sep 29, 2021 at 10:20 AM
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JEREMY400
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150 not 159.
Sep 29, 2021 at 10:21 AM
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JACOBANDNICKOLAS
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Hi,

I noticed it has been a few days since we heard from you. Have you been able to make any progress? We're interested in knowing.

Also, if you have an exhaust leak near the oxygen sensor, it could be causing the computer to think it is running lean. Do me a favor. If you have a live data scan tool, let me know what the short-term fuel trims are. Also, let me know if the coolant temperature sensor is signaling correctly. One last thing. Are there any diagnostic trouble codes stored and have you checked for a vacuum leak? Here is a link showing how it's done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

The engine compression readings you provided look good.

Let me know.

Joe

Oct 2, 2021 at 1:16 PM
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JEREMY400
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I actually just ordered an Autel scan tool that is capable of watching data. I did look for a vacuum leak, but I am going to look again. I have a feeling that’s what it is. The only code is for a downstream O2 sensor. It’s been there before I did this repair. There is a small exhaust leak by the sensor. So, it does drive but it shakes bad. I took it down the road the other day. Appreciate the help!
Oct 4, 2021 at 8:50 AM
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JACOBANDNICKOLAS
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Hi,

Happy to help. I think the first thing we need is the short-term fuel trims. Once you get the scan tool, let us know what you find.

Take care of yourself,

Joe
Oct 4, 2021 at 1:05 PM
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JEREMY400
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So, I borrowed a friend’s scanner. Here is a picture and a new code jump popped up. It’s on the screen. So, wouldn’t bank2 short term trims be a little high? Running lean? Thanks.
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Oct 7, 2021 at 9:01 AM
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JACOBANDNICKOLAS
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Hi,

Bank 2 is a bit high. It isn't at operating temperature at this point. Check it at approximately 200F.

Now, the code indicates an issue with the EGR. That can be causing a lean mixture or even a vacuum issue. I attached the directions for the diagnostics below. Take a look through them and let me know if you are comfortable performing them.

Let me know.

Joe

See pics below. Don't be overwhelmed with the directions. Hopefully, you won't need to go through all of them. They are very detailed for every possible issue. Also, I think you found the issue. I suspect there is an issue with the EGR itself.
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Oct 7, 2021 at 10:48 AM
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JEREMY400
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Hey, so I did go down the list and there was power to the EGR so I changed it. P1406 is gone but the truck still runs rough. Bank 2 stft jumped up to +13. There is a gas smell. Someone told me to pull the intake and make sure none of the injectors popped out of the ports. With good fuel pressure could that have happened?
Oct 18, 2021 at 10:44 PM
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ASEMASTER6371
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That is possible but it also may be the fuel pressure regulator on the side of the spider.

Check and see if it is dripping fuel from the vacuum port.

Roy
Oct 19, 2021 at 6:23 AM
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