2007 Expy P0308 code

[n2umr]

I recently have been getting a p0308 code for a misfire on the #8 cylinder. Here's the catch, it only happens when the engine is very cold and you give it more than 50% throttle and it is still very sporadic. Once the engine starts to warm up the it never happens until I let it set overnight again.

So I initially thought that the coil was bad, I bought a new one and no change. I put some injector cleaner through it thinking it might be an iffy injector, no change. I guess I will change the plug and see if that makes a difference.

If the new plug doesn't work anyone have any other ideas?

Mark

 

[Stoned06]

My guess is the plug. My 2006 got the misfire code and I replaced both the plug and COP. The plug tip was quite a bit smaller than the replacement one, so I assume that is where my issue was.

 

[n2umr]

Boy you weren't kidding. I took the old plug out and there was almost no electrode left. I though these we suppose to last 100000 miles, I just rolled to 60k. BTW, it fixed the problem. Now I'm wondering if I should just replace them all. Thanks.

Mark

 

[tmajikman]

Boy you weren't kidding. I took the old plug out and there was almost no electrode left. I though these we suppose to last 100000 miles, I just rolled to 60k. BTW, it fixed the problem. Now I'm wondering if I should just replace them all. Thanks.

Mark

Yes, replace them all, if one looked like that, they could all look the same, make sure you torque the plugs to 13 foot lbs. if not you could pop a plug out.

 

[n2umr]

DO these plugs have the same problem with breaking off in the cylinder head? It took quite a bit to get this one out but it came out in one piece.

Mark

 

[Stoned06]

DO these plugs have the same problem with breaking off in the cylinder head? It took quite a bit to get this one out but it came out in one piece.

Mark

YES!! Be careful and use plenty of PB Blaster/WD40 or something similar. Give it a couple of short twists, then spray some lubricant in there. Wait, thread back in , work it back out, etc, etc, etc.