SOLVED: Another misfire chasing threads (2008 express van)

[Tonyv__]

Details
2008 Chevy express 3500 cargo van 6.0
58k miles. 8k running hours. No service history

So after last weeks fun with the wife’s MB. (I think it’s resolved). my work van started having a rough idle. Code reader says P0307 misfire cylinder 7 confirmed. So I went and changed out the spark plugs (gapped to .040) and new wires. And did a half ass compression test because I didn’t realize how tight everything was. I tested the back 4 cylinders. All within 175-180psi. After this. I have p0302 code. Cleared then it came back. And it’s actually noticeably worse than it was before I changed the plugs. Now it rough idles then hard shifts into 2nd gear when accelerating from stop. Where oh where do I go from here

I originally had plans to move the coils around to see if the misfire follows. But I didn’t even get that far. And now it has gone to cylinder 2

Any advice is greatly appreciated

 

[Tonyv__]

Solved. My mechanic is an idiot. (I’m the mechanic) Cylinder 2 is the absolute hardest cylinder to get to on these vans and when I pulled the spark plug. It had zero gap. I must of banged it around trying to get it threaded

 

[OR VietVet]

You beat me to it. I was gonna suggest you recheck your work since it only had the misfire code for the one cylinder when you started. Then after the work you had a problem on a whole other cylinder. The coil swap would have been a recommendation as well. Glad it worked out for you.

 

[Tonyrodz]

My express van is a pos too.

 

[OR VietVet]

My express van is a pos too.

Yea, I have seen you speak highly of that van before.

 

[Tonyrodz]

Yea, I have seen you speak highly of that van before.

It idles at around 450 rpms. Maybe the cats are clogged. Has the 4.8 with only 150,000 on it.

 

[grouch]

It idles at around 450 rpms. Maybe the cats are clogged. Has the 4.8 with only 150,000 on it.

Hook a vacuum gauge up to it. That will tell the tale of the exhaust condition. As for zero gap. You didn't bang your head on the plug from frustration did you?

 

[Tonyrodz]

Hook a vacuum gauge up to it. That will tell the tale of the exhaust condition. As for zero gap. You didn't bang your head on the plug from frustration did you?

No as far as I know, the gaps are fine. I did get the plugs from Amazon, so who knows if they're legit. Someone tested the cats for me--they're def clogged. I gotta hollow them out. I've changed the maf and the tb twice, thinking that was the issue--it's not. When I changed the plugs about 2 1/2 yrs ago I also changed to oem wires. Driving it home after buying it a P0300 popped up--and it's been haunting me ever since.

 

[OR VietVet]

No as far as I know, the gaps are fine. I did get the plugs from Amazon, so who knows if they're legit. Someone tested the cats for me--they're def clogged. I gotta hollow them out. I've changed the maf and the tb twice, thinking that was the issue--it's not. When I changed the plugs about 2 1/2 yrs ago I also changed to oem wires. Driving it home after buying it a P0300 popped up--and it's been haunting me ever since.

@Tonyrodz, I think he was referring to @Tonyv__ about the spark plug gap on #2 cylinder when he had changed plugs for a cylinder #7 misfire code and then had a misfire code for #2 and pulled plug and found it had a pinched gap.

 

[Tonyv__]

@PNW VietVet I might as well of smashed them on my head... before I bought the van I always wondered how would I service the engine..... there’s an engine cover inside the van.. except it takes 20 minutes to get to it.. you have to remove the passenger seat, remove 2 lower dash panels, remove cup holder/glove box assembly, then the actual cover comes off.... at this point I’m ready for a coffee/beer break

 

[OR VietVet]

You have to remove the passenger seat? What kind of hokey crap is that? Engineers can be idiots at times. I would not have one of those vans on a bet.

 

[Tonyrodz]

You have to remove the passenger seat? What kind of hokey crap is that? Engineers can be idiots at times. I would not have one of those vans on a bet.

You don't really need to remove the seat, but it makes it so much easier and manageable if you do. I do the same thing.

 

[Tonyv__]

You have to remove the passenger seat? What kind of hokey crap is that? Engineers can be idiots at times. I would not have one of those vans on a bet.

I really considered the Nissan vans because of engine accessibility. But when I was searching online reviews. A lot of people made a valid point that the Nissan vans sacrifice a decent amount of cargo to have a full size hood in the front... and also cost was a major factor as well..

Unless you’re flexible, that passenger seat needs to come out lol. If I’m not mistaken. I think you can only slide the cover up a foot or so if you leave the seat in. The seat needs to come out to completely remove the engine cover out of the way
.

 

[Tonyrodz]

I really considered the Nissan vans because of engine accessibility. But when I was searching online reviews. A lot of people made a valid point that the Nissan vans sacrifice a decent amount of cargo to have a full size hood in the front... and also cost was a major factor as well..

Unless you’re flexible, that passenger seat needs to come out lol. If I’m not mistaken. I think you can only slide the cover up a foot or so if you leave the seat in. The seat needs to come out to completely remove the engine cover out of the way
.

I also like thise Nissan vans, especially the ones you can stand up in, but they are pricey.

 

[Tonyv__]

So I’m back to the misfires.. cyl 7 started acting up on me. Changed coil wire and plug with cyl 8. No change. So I pulled the fuel injectors and swapped 7 and 8. Currently idling the van for 15 mins or so to see if the code comes back in 8 instead of 7. Don’t have high hopes…. If no change, what’s the next step? Pull the valve cover and check the valves?

Oh yeah compression is good across the cylinders

 

[OR VietVet]

Check for vacuum leaks too. How old are the plugs?

 

[Tonyv__]

Check for vacuum leaks too. How old are the plugs?

January of this year and only 5,000 miles. I did plugs and wires.. follow up also the misfire did not change cylinders even after fuel injector swap.

how do I check for vacuum leak

 

[OR VietVet]

I check for vacuum leaks with my ears and I like to use a mechanic's stethoscope and take the probe out of the end of the hose and use the hose to search with. Another way is to use water in a spray bottle and spray near areas where there could be a vacuum leak and listen for the idle pitch to change.

 

[Tonyv__]

I check for vacuum leaks with my ears and I like to use a mechanic's stethoscope and take the probe out of the end of the hose and use the hose to search with. Another way is to use water in a spray bottle and spray near areas where there could be a vacuum leak and listen for the idle pitch to change.

I just YouTubed something briefly. Should I check for leaks around the intake?

 

[OR VietVet]

Intake is where to start for sure. Any vacuum hoses in the area.