Odd engine miss.

It starts and idles just fine, in town it runs ok. But on the freewy at steady speed it will miss. The VAC will jump between about 20 and 10, it feels like it's shuting off. But if I accelerate it clears up. It only does this at a light load, steady speed.

What is diffrent about the stedy speed running condition???

Parts replaced; crank position sensor, plugs, plug wires, cap / rotor, injectors, PVC system.

I get several OBII, codes all just say miss fire, but no useful info about what might be causing the problem.

Any ideas???

 

Did you gap the plugs correctly?

 

Did I gap the plugs, yes, and I have been changing the plugs often, about evey 5,000 miles.

I have had this problem for over a year, sometimes it seems to clear up, then the next day it will be worse.

It's worse at steady speed, light load.

Even with a bad miss it doesn't give a code for O2 sensor out of range, just missfire codes.

It starts fine, idles fine and in town it seems to be OK, but on the freeway at steady speed light load, it will miss fire real bad. So what is so diffrent at steady speed/light load.

At light load there is very little air flow, so a small air leak could cause a problem, but that should cause a 02 sensor out of range, should effect mixture, but I don't get that code. just missfires.

 

Are you using Genuine Volvo spark plugs? And you don't really need to change plugs that often. My Dad's car had the original plugs at 150k miles until they needed replaced.

 

....well actually on 2nd thought

 

yeah, how silly for me to think that using non OEM plugs could cause a miss. DUH, I keep forgetting that boostcreep knows everything.

 

Dude your such a moron.I and many others use non-oem plugs with great results.Never had a miss once using NGK plugs.I know thats hard for you to grasp being the noob that you are and seein as you didnt know that these cars have heat shields in the back and you dont know how to get a OBX system installed without having rattles.Really? Dont you want me to continue to clown you more?
And telling someone its ok to leave plugs in for 150k thats just plain stupidity.But o yea you are a complete moron so thats no surprise.

 

Uh, had no problem installing the OBX, the rear heat shield over the muffler rusted out causing the rattles, nothing to do with installation. I am running non oem plugs as well without a miss, and many people do run non oem plugs without a problem. But there are also many people that have installed non oem plugs, experienced a miss, installed oem plugs, and the miss was gone. And I didn't tell him to leave his plugs in for 150k miles, I said that you do not need to change them every 5k miles, and as an example, I told him my Dad's car's situation. By no means should anyone leave their plugs in for that long.


I wrote it all in bold so hopefully you could understand it better, I know it's not in caps, but this should suffice.

 

lol sure.I read what you posted on VS dude.Dont try and make stuff up now.

And if someone had a miss with non-oem plugs it wast because they werent OEM it was because they werent gapped right moron.

 

Make what up? That I didn't know there was a heat shield above the muffler? Your right, I didn't know that, but the fact that it rusted out and was sitting on the exhaust had nothing to do with installation. Not trying to make anything up....dude.

 

 

:rolleye faces when I have nothing better to say:

dude

 

Already said what needed to be said.Your an idiot plain and simple.

You put out mis-information then try and say you didnt say it when you get called out on it.

Even funnier you are saying that you didnt have any problems with the OBX and that you knew about the rear heat shields when in the VS forums post you completely said the opposite.

 

What? That non oem plugs can cause missfires? That's not mis-information. It's true.

I didn't have any problems with the OBX. I actually have no problems with out, although I have to bend the heat shield above the turbo back everyone once in a while, it's been completely fine. And I never said I knew about the rear heat heat shield. Here's the link, if I knew about it, I would have never asked:

http://volvospeed.com/vs_forum/index...e__hl__exhaust

No where do I say I know about the heat shield in the rear, and I just said before that I didn't know about it. I don't know why you keep making things up to try to call me out on them. Just makes you sound like a bigger dumbass than you already are.

 

O really? I've used several non-oem plugs and never had a misfire @ 17psi.
You have no clue wtf you are talking about and thats a fact.Your a moron of the highest degree.Good day noob !

 

 

lol. Just because you used oem plugs and didn't get a misfire, doesn't mean it's the same for everyone else. I've read several threads about misfires being fixed by switching to OEM plugs. Just because you think you FOREVER BLACK is the best, doesn't mean it is. Get off of your high horse. Good day noob! lol. You crack me up.

 

Awesome pictures. They really portray what you are trying to say way better than words. You have a really nice library of those. Cool pictures dooood.

 

Figured they would help since your too stupid to understand words.

 

Do a compression test, make sure all cylinder are very close in there pressure.