Tracking down a misfire

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Duke Silver

Member
Joined
Jul 31, 2024
Posts
44
Reaction score
37
Hey guys,
For any of you that even follow any other threat I've been posting on here, specifically the one where I was replacing my knock sensors towards the end there I gave a little bit more information so I'm going to try to get some information right now with everything that I've done regarding this misfire I've had ever since I bought the car back towards the end of March beginning of April.

But I purchased the car it was out of liver off I was pulling a code for a misfire I thought No big deal I will replace the plugs, wires, and coil packs. That didn't work. I was told to listened to the fuel injectors and all of them are making the ticking noise they're supposed to make. Since I don't have one of those nice expensive scanners I couldn't see where it was coming from or figure out what the problem was I took it to a shop, The mechanic there said it's misfiring on three mainly but a little bit on one as well. He tried to swap around the wires and the misfire did not move. He recommended another shop because he doesn't deal with what the issue he thinks that it is, which he said is a possible engine rebuild but I'd have to get a compression test done so I tried to call this shop these guys just kept giving me a runaround I gave up on them and decided to do the compression test myself. Now I do apologize here I do not have the numbers I feel like doing the compression test again. If my memory serves me correct I don't think anything was too far off, I was having a hell of a time trying to get the hose screwed into cylinder 5 but I also have a hard time trying to get the spark plug in as well despite the fact that I can't get the spark plug I couldn't get the hose in. I do remember the first and third cylinder having higher compression than any of the rest The other ones were all pretty much on point with one another. Let's say the other ones were all somewhere within a 120 to 140 range these two might have been closer to 200. This was a few months back so I cannot recall entirely, I do apologize. At this point I've been driving it around with that rough idle and getting the misfire code from time to time until the check engine light one day started flashing in the car started acting like it was going to stall I scanned the code again with my cheap scanner and that's when I pulled up the knock sensor problem. I thought maybe this is what has been the issue since everything I started reading about the knock sensor said it can cause a rough idol at misfire. Well those were replaced This past weekend and while I was doing that that I also replaced the valve cover gaskets.

Since last Sunday I feel like the car has gotten worse regards to this misfire/rough idle. But I had it up on the highway before it felt good now I haven't had a chance to get to a friend of mine who has a really good scanner tool to try to monitor the misfire while I'm driving, because we did that before and the misfire was going away when we would pick up speed, The second it starts slowing down or comes back to idle that misfire comes right back. Now when I'm up on the highway I can feel how rough it's running. In city traffic it's pretty brutal especially if it's been warmed up for a little while It's the point where I'm getting that chugging feeling like it wants to stall extreme lack of power. And now getting to the park that really pains me I'm starting to hear that clicking ticking noise so I'm thinking this might be a lifter issue. I wasn't getting that prior to all the work that was done to it last weekend.

I am by no means a skilled mechanic I'm trying to learn Not only to save myself money but because it's something that I wanted to do my entire life. After watching a few videos and doing some research it looks like I can pull the valve covers and do two things, I can fire up the engine and see if the rocker arms are all moving at the same rate, or I can see if any of the rocker arms have play in them and from what I understand it seems like if they have play that means that the lifter is bad If I'm not mistaken.

With all that being said if the lifters are bad And I've had this car since March/April who knows how long the previous owner was running this thing around I'm going to go out on a limb here and say more than likely the camshaft needs to be replaced as well. I figure I already have money into this vehicle so there's no point to try to get rid of it just to try to get another one that might have its own set of problems. I'd rather try to solve the issue if possible. Thanks And sorry for the lengthy post.

One thing I forgot to mention if you didn't see it in the other thread or I'm discussing the knock sensor replacement. I recently discovered that the catalytic converters are clogged as well. I'm driving around especially at lower speeds let's say like a parking lot speed I get that horrible vibrating rattling noise coming from under the car and from time to time I'm smelling the rotten egg smell. Temporarily what I was planning on doing was cutting out a hole hollowing out the cats doing the defouler trick and then just having my brother-in-law welt the plates that I cut out back on just to buy me some time until I can get up some money too replace the cats and at that point I might as well just replace the muffler I was thinking about going with something along the lines of a magnaflow system.
 
OP
OP
Duke Silver

Duke Silver

Member
Joined
Jul 31, 2024
Posts
44
Reaction score
37
And I knew I would forget to add the info about the vehicle. It's a 2005 Suburban LT 5.3 (Vin Z), it has close to 197,000 miles on it
 
OP
OP
Duke Silver

Duke Silver

Member
Joined
Jul 31, 2024
Posts
44
Reaction score
37
Another update for today, I pulled the valve cover off to take a look at the rockers. For some reason I'm having a hard time with it uploading correctly to imgur, so I've attached a Google drive link to the video. None of the rocker seem loose as they said they would be if there was an issue and they were stuck. They all seem to be moving well in my opinion. Don't know if I should dig any deeper into it being a lifter issue or if I should move on and start messing with the catalytic converters.

 

kbuskill

***CAUTION*** I do my own stunts!
Joined
Mar 11, 2017
Posts
5,292
Reaction score
8,280
Location
NE. FL.
Another update for today, I pulled the valve cover off to take a look at the rockers. For some reason I'm having a hard time with it uploading correctly to imgur, so I've attached a Google drive link to the video. None of the rocker seem loose as they said they would be if there was an issue and they were stuck. They all seem to be moving well in my opinion. Don't know if I should dig any deeper into it being a lifter issue or if I should move on and start messing with the catalytic converters.

Ever get a chance to check that coil bracket harness I mentioned?
 
OP
OP
Duke Silver

Duke Silver

Member
Joined
Jul 31, 2024
Posts
44
Reaction score
37
Ever get a chance to check that coil bracket harness I mentioned?
Yeah same day I pulled the valve covers to take a look at how the rocker arms were moving I checked it out everything looks good. Trust me I'm praying for a simple stupid solution but knowing my luck I have a feeling it's going to be something along the lines of a rebuild or more than likely just buying a rebuilt engine.
 

Fless

Staff member
Super Moderator
Joined
Apr 2, 2017
Posts
11,720
Reaction score
23,785
Location
Elev 5,280
Hey guys,
For any of you that even follow any other threat I've been posting on here,

Recommend not posting threats here... ;)

Seriously, if it hasn't been done, put a scanner on it that can read single cylinder misfires. Consider doing a CASE relearn. And it sounds like the cats might need help, if that was a good diagnosis.
 

Forum statistics

Threads
132,020
Posts
1,861,093
Members
96,459
Latest member
Ajnwow
Top