Misfire in cylinder 8


ndnwarpony
01-11-2004, 03:26 PM
Hello folks, I was wondering if I would be able to get some help from you guys. I have a 2000 Chevy Silverado 5.3 with 2 codes of a misfire in cylinger 8. The idle was rough after a quick drive and thats when all of this started. I replaced the spark plugs with Autolite Platinums about 2 months ago. I bought some new wires and swapped them out yesterday but that didn't fix the shudder problem. Could it be that the plug burned out or something? and where is cylinder 8 anyway? I still have the old plugs and was wondering if I could just find cylinder 8 then I could swap out an old plug just to see if thats the problem.

Slowprocess
01-11-2004, 04:15 PM
There is a list of things that could be making this happen.

1.The poppet valves after the injectors are prone to getting clogged so run some techron through it.
2.Bad plug or gapping touble
3.clogged fuel filter
4.You may of got some bad gas. did it start happening after a fil up?
5.Could be a clogged EGR valve
6.Possibly a vacume leak around where the egr goes into the throttle body.

I would suggest several things to try.
1.while its running pull one plug wire off at a time to figure out which cyl. is giving you the miss.You might want to swap plugs on the misfiring cylinder to see if its a bad plug.
2.If this doesn't help, but you have located the cylinder,then do a compression test on the dead hole that you find.and or swap coils
3.If it is isolated on that one cylinder, swap the coil packs to a different cylinder. See if the misfire moves with the coil. You could move injectors as well.

H.tech
01-12-2004, 04:30 PM
If whats happening to your truck started after you took it for a good fast run it could possibly be your timing is off thats what i can say i meen if its misfirering other than that like the other guy said it could be your injectors

tidalcock
01-12-2004, 08:36 PM
Don't forget to check the plug wires also.

RacinRex
01-13-2004, 08:37 PM
When you are looking at the motor, 8 is clear in the back on the left side.

ndnwarpony
01-14-2004, 12:52 PM
Well, I replaced the plug in number 8...still the same...so nothing wrong with the plug. I replaced the wires and still the same. I put some fuel injector cleaner in the tank with some more gas and took it for a drive for about an hour and still the same. Now I'm thinking about swapping the coil pack off of the #1 cylinder with #8 cylinder and see if the misfire follows that coil. I don't have a code reading device and Autozone is happily running the codes for me. Is there a simple way to test out the valves that are listed in the first reply? Like the EGR valve and others?

Slowprocess
01-14-2004, 01:05 PM
The egr valve is is bolted by two bolts into the side of the throttle body. I believe it's two little bolts. Once you get these bolts undone, you can just pull out the valve to see if its clogged up. Just look for a hose that is connected from the passenger side manifold to a small pump. The aluminum hose from the pump to the throttle body is where the egr valve is.

ndnwarpony
01-14-2004, 01:23 PM
Cool...I'll go out to the garage during my lunch break and check that out. From the way you're describing it, it sounds as if it'll be physically clogged, I mean visibly where you can see that it's plugged up.

ndnwarpony
01-14-2004, 02:39 PM
I found the valve and removed it from the engine. There were no signs of blockage, just an intake opening and on the other side a spring like valve that seemed to move freely. Is there a simple way to see if this is working or not? How about the injectors SlowProcess, is it fairly easy to swap or check to see if it's functioning or not?

Slowprocess
01-14-2004, 04:48 PM
If it looks pretty clean and the spring seems to move freely, and you've checked all of the spark plugs and wires, it is probably going to be the coil. It's easy to switch them to another cylinder. Just switch the number 8 with another cylinder and see if you get another code to come up. If another code comes up(different from the other two codes you were getting), then you know that it is the coil that has gone bad. I'll ask some buds to see if there's anything else that might throw the codes. In the meantime, change over the number 8 coil with another one and have autozone run the scan. It's most likely there.

ndnwarpony
01-14-2004, 07:45 PM
well folks, I switched out the coil pack with #5 and #8 and no change in the error code. Actually, there was another code that was added again which showed up once and was gone the at the second code reading, bank 2 of a low voltage in the O2 sensor was detected along with the misfire in cylinder 8. What would you guys recommend I do now?

covvy
01-14-2004, 09:57 PM
Well if you are getting a bank 2 lean (low voltage) and a #8 misfire then odds are that you have an intake leak in the vacinity of that cylinder. Use some intake cleaner and spray the seam of the intake and watch for the idle to change. If the coil is ok as you have shown by the comparison and the plug looks good then its either a bad fuel injector or intake leak. Odds are that its the intake. Check all vacume lines that directly effect that cylinder. Good Luck.

radioralph
01-17-2004, 05:52 PM
is this an interminent problem that clears up after engine runs for a couple of minutes ?

ndnwarpony
01-18-2004, 12:17 AM
Hey radioralph, no this is a good failure....it hasn't cleared yet or run smooth since it began. What do you think might be the problem?

radioralph
01-18-2004, 09:59 AM
I am having a similar problem with a misfire #7 ..but it clears up in 1 minute or less,I also sprayed intake in the #7 area to check for vacuum leak which indicated no leak,so I guess I will do what you have done to try to correct the problem my truck just turned 97,000,good luck...RadioRalph

MSpring
01-30-2004, 01:58 PM
did you find ut what the problem was?

radioralph
01-30-2004, 05:46 PM
I have installed new ac-delco plugs and wires and cleaned EGR valve and the service engine soon light reset.... drove truck 1 week to,from work,total of 125 miles and the SES light is back on....I have not checked to see if the code is still misfire in cylinder 7 or a new code... it's been TOO cold in S. Georgia

ChevyLeadFoot350
01-31-2004, 11:17 PM
Hello folks, I was wondering if I would be able to get some help from you guys. I have a 2000 Chevy Silverado 5.3 with 2 codes of a misfire in cylinger 8. The idle was rough after a quick drive and thats when all of this started. I replaced the spark plugs with Autolite Platinums about 2 months ago. I bought some new wires and swapped them out yesterday but that didn't fix the shudder problem. Could it be that the plug burned out or something? and where is cylinder 8 anyway? I still have the old plugs and was wondering if I could just find cylinder 8 then I could swap out an old plug just to see if thats the problem.

you could just change all the spark plugs, that will solve the problem if its the sparkplug in cylinder8.

ndnwarpony
02-02-2004, 09:18 PM
Well folks, I started messing with my truck again. I finally think I found out what the problem is now. While the truck was running I pulled the wire off of the injector at cylinder 4 and the truck ran worse, so I plugged that back in and it went back to the way it was running. Then I pulled off the wire connection to the injector 8 and there was no difference in the way the truck was idling. Soooo, I figure that that injector, cylinder eight, is clogged and not letting any gas through.....do you guys think this has happened? About a month ago, I ran out of gas and think some crap from the bottom of the tank got pass the filter and into that injector and clogged it.....what do you all think?

radioralph
02-03-2004, 09:04 PM
I believe you are going in the right direction... I used GOOGLE search, entered chevrolet cylinder misfire which led me to a site that gave details on using a digital volt ohm meter to check the coil that is inside the injector... good luck...

ndnwarpony
02-03-2004, 09:13 PM
Well folks, I think this chapter on my side is through with in this thread. Last night I used a stethoscope that my cuz had, I put one end of a screwdriver to the injector and on the other end the stethoscope. I heard all of the injectors working, to my surprise...lol. Sooo, my theory on the clogged injector was incorrect. Then, I bought a fuel filter and went on to replace that one first and WALLA!! The truck was idling correctly!! A clogged fuel filter was the cause of this whole thread...can you believe that?? Well, it's a good thing I didn't pay $90.00 for a diagnostic, I would've been kickin myself in the #$$ for that deal...$14.00 for a fuel filter and now I'm good to go.

jason1sawyer
03-10-2004, 10:47 PM
Gm Has Faulty Fuel Injectors In 96-2001 Trucks, Suv's And Vans And They Know About It. It's So Bad California Has Forced Them To Recall All Those Models With Hesitaion And Rugh Starts. They Claim This Is Not A Recall But They Are Forced To Clean Or Replace The Old Injectors With New Ones That Are The 2002 And Up Models.
Root Cause For All The Hesitaion And Rugh Starts Is The Poppets At The End Of The Injectors Either They Stick Open Or Stick Closed.
After Intense Reseach Online And Numerus Phone Calls To Dealers I Have Found That We Can Change In Convert The Fuel Injector System To The New Style. All You Have To Do Is Call Any Dealer And Give Them This Bulletin # 00-06-04-003b
This Is The Convertion Bulletin.

desertmike1
03-11-2004, 01:20 AM
Recomended fuel filter change---> 30K miles!

ndnwarpony
03-11-2004, 07:34 AM
Gm Has Faulty Fuel Injectors In 96-2001 Trucks, Suv's And Vans And They Know About It. It's So Bad California Has Forced Them To Recall All Those Models With Hesitaion And Rugh Starts. They Claim This Is Not A Recall But They Are Forced To Clean Or Replace The Old Injectors With New Ones That Are The 2002 And Up Models.
Root Cause For All The Hesitaion And Rugh Starts Is The Poppets At The End Of The Injectors Either They Stick Open Or Stick Closed.
After Intense Reseach Online And Numerus Phone Calls To Dealers I Have Found That We Can Change In Convert The Fuel Injector System To The New Style. All You Have To Do Is Call Any Dealer And Give Them This Bulletin # 00-06-04-003b
This Is The Convertion Bulletin.

Hi Jason, so all would do is call up a dealer and tell them about this Convertion Bulletin and they'll replace my fuel injectors?? This has nothing to do with warranty?? Did you have yours replaced?

J-Ri
01-19-2005, 10:12 PM
Did they go to the coil over plug design? Just curious...

If it has the 4 coil packs with 2 plugs per coil, you'd be missing on number 5 also.

J-Ri
01-19-2005, 10:16 PM
oops... I guess I only read the first page

I am still curious about the coil design.

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