Possible HG failure.

Morning all,

I get to ponder this for a whole 2 weeks. Since I'll be out of town for business...
07 285k 5.7L 2wd
A few days ago I started getting a smell of exhaust fumes coming from the passenger side vents as it was on heat, driver side on cool. Assuming it's possibly the passenger side exhaust manifold coming loose and getting sucked in by the intake. I have not checked, but when I did the starter a few years back several bolts were loose, yes they were retorqued.

Eitherway I've noticed a slight miss as the idle gets rough for a second and goes back to normal. I was sitting at a stop light when I started noticing a shake. At a certain point it started to miss in sync with the compressor kicking in. Calculating in my mind I turned off the AC and it settled for a few minutes but continued to miss after 2 minutes. Pulled out the OBD2 to start a live scan and look for codes. No codes, Live data appeared normal. So, I go into Mode6 while sitting in a parking lot and can feel the misses. Assuming it's a head gasket, but mis fires on both banks lead me to believe a chain stretch??

 

slow down a bit. Check the easy stuff first. Misfires can be a lot of things. I'd start with ignition. Check plugs, move some coils around, etc.

 

yes, I can't do anything atm, lol.. just spit balling right now... I'll have to do this at midnight when I get back and travel 60 miles home.

 

Updating this.

I got back late last night and quickly realized there was really no point in trying to troubleshoot shit since you can't see shit. So, I gambled and drove it home, not too big of a deal.

This is intermittent, I turned on the truck and had 1 misfire event using Mode6, using Bluedriver OBD2, idle was good no, vibration. Going up the mountain I had no codes, 25 misfire events 23 just in cylinder 5. Going higher, transmission dropped 2 gears and demanded more power from the engine and got a "permanent" and flashing CEL P0305. No change in driveability. Pushed home.

Driving in streets, whole different beast. Idle was rough and you could feel the misfire, bed bounce was heavy as well. Vibration was heavy above 40mph. Simple fact that I didn't want to be stranded at 3am while my truck is towed I'd have to huff it home since you can't ride along.

Got home and this thing is shaking pretty bad. Parked and went in, night ended with 1,570 misfires, 1567 misfires on cyl5, 1 misfire on cyl 1 and 4.

This morning I went out to swap coils. Well lets just say I no longer need to swap coils, I need to replace them. Cyl 5 could be the only one, but since 1, 3 and 4 were also being impacted, odds are I will replace them all at once. Clip was caked on there and will not release, so I will need to use some force to remove that clip. BTW, code went away no CEL.

 

Post more pics please.

 

As of now, thats as far as I went, couldn't separate the clip from the coil, on top and had other stuff going on, but will probably go all in tomorrow morning. I don't have any spare coils at the moment, so I may need to let her be for now.

 

Update: It may be the spark plug. Spark looks toast tbh, coil appears worn, but functional. I don't remember the last time I changed my sparks, but I thought I had like 10k +/- more miles will need to do them soon, since cyl 5 is now new. After 1st drive, it appears that misfires are

 

Pictures are taking a while to upload. Top is before, bottom is after spark plug replacement. Total difference of about 200 less misfires. There is vibration that has gone away going uphill.

 

There appears to be some build up on the tip of the spark plug, maybe just wear. This was a rush job, just did this one for now.

 

Doesn't look good at all. The electrode and strap look trashed. How old are those?

 

LMAO. yes, they're original, so.... 16 and a half years old.

 

Wait, the sparks??? they're probably 3 years old?? They're probably 80-85k miles..

 

For the record I buy spark plugs through the auto parts store Oreilly's for these pairs since it was across the street from my house. Usually NGK, although these may be another brand, I don't remember, I'll clean it and advise. Cyl 3 and 7 have joined the party, so in total 1, 3, 4 and 7 have misfires. Although, single misfires but a sign. Cyl 5 has misfire counts but less of them. Only driven in twice, so maybe it's auto deleting positive functions over time?. Will know by Friday, Saturday I'll replace all 7 of them and maybe swap the coil to remove any doubt.

 

use only Denso or NGK Iridium plugs. Nothing else.

 

Denso Iridium for me

 

Welp... They're Autolite XP Iridiums.... I'm at a loss tbh, lol.... I'm usually buying NGK plugs tbh, but this may have been through that time I was getting evicted for paying my rent on time and to the leasing company I had a contract with. In that case these plugs are probably 5 years old and I was in a pinch financially. lol..

 

Replaced the rest of the spark plugs on bank 1. 3 and 7 have build up oil, so I'll need to do the gasket there soon. I'll do bank 2 later or in parts depending on what I have going on. Cyl 3 had sludge on the coil area. I cleared all codes, the last read was 300 misfires, 244 on cyl 5 before clearing it. After I have a single misfire on cyl 1. Does get me a little worried, but may need to swap the coil, although it's the cleanest one, also swapped coil 5 with 7, so far so good.



plug 1


Plug 3


Plug 7, The dirt cap was while removing it, made contact with camshaft cover.

 

You should get more money back on increased MPG alone. Did you double check the gap before installing them? Only a few times over the last several plug changes I’ve done on cars did I ever have to adjust one or two. Just never know.

 

Yes, always do this before they go in, will check the old ones for grins.

 

Completed Bank 2 this morning. My kid must've turned in his early up credits yesterday. Eitherway, Bank 2 was more interesting. Alot more gunk or sludge on this side. Cyl 2 and 8 pulled the gasket out of my spark plug socket. Well final outcome is the truck is a lot quieter.... I was hearing some loud ticking or what I thought wass the timing chain tensioner.. more like a diesel sound minus the cool turbo sounds.

Top down coil 8, 6, 4, 2

plug 8, 2, 4, 6 oil build up on 8 kidnapped 1 of my sockets.

There is still a single misfire on 7, 4 and 2. This will bring up the camshaft gasket will need to be addressed. Sooner rather than later. I do have gasket maker, but may go with Fel-pro since I don't think there is a gasket for it.

 

Quick question referencing these 2 plugs. Could it be RTV? Starting to come undone? Or sludge? Reason I ask it was extremely sticky and appeared mainly on cyl 1, 2, 7 and 8. None on 3-6

 

After my 1st full tank of Costco 91 gas. I dropoed an insignificant amount of MPGs from 13.5 to 13.4 with a full tank on all new sparks, 15.5 A whole 2 miles per gallon, I call it a win.

 

Update #2 Took a long trip this week and averaged 16.9 to 17.1 mpg, got more than 300 miles to the tank. Although I encountered heavy rain and a transmission issue where I lost 1st, 5th and 6th gear at certain points. All gears returned after a short break. Will follow up on my 3 year old thread based on this issue.

 

Those coils look worse than mine did at 195K!

 

LOL, they're still there.. Not having an issue as of yet. I get the occasional single misfire on certain cylinders but no more real misfire issues. If they start adding up I will pick up some Denso coils and replace them.

 

Do your valve covers leak? I never have any dirt or grime around outside of my plugs.

 

Yes they do. I'll be doing them next.

 

Well I’m glad that solved your misfire issues. I would replace those coils if I were you before they start causing problems.

 

Yes. I've ordered a new set out of rock auto, but wont be swapping them until I do the valve cover gaskets.