Poping or Misfiring Under Hard Accelearation

[Jackpine]

Henry, I'm sorry if what I said sounded like the "idiot treatment". It was just that I was not sure if you were getting repeated "thumps" (like: thump, thump, thump, ...) or only one.

In your last post, what you described really DOES sound just like what I've experienced now and then. I felt it maybe twice on our recent trip to and from California, in moderate traffic, when I would accelerate to move quickly into a passing lane. I can hear it and I can feel it, and it sounds like it's something going on behind me.

I wonder if there's any way it could be coming from the differential? (I assume you have traction lock, like I do)?

- Jack

[svt2205]

No worries Jack, I know you're trying to help. Sometimes it's hard enought to describe things when you're talking directly to someone. It's even worse when we communicate via email or posting on sites. I always try to take it all in stride, knowing that most folks are only trying to be helpful.

I'm still thinking it's engine related, as the noise has gone away, since returning to stock. Then again, it's also only in the 30's again, so we'll see when/if it ever warms up again.

Thanks again for your thoughts and help. It's greatly appreciated
Henry

[svt2205]

FWIW, I wemt from stock back to Level 2. Whatever this is, is still there. I'm going to see if I can narrow down exactly what the heck my truck is doing.

[soutthpaw]

I see Bill asked this but don't see an answer. Can you easily repeat the occurance. For example every time you give it more than 50% throttle from a stop you get the thumping??? if so what are the exact conditions that it occurs at. This is very useful info in diagnosing the problem...

[jimmyv13]

Maybe a COP???

[svt2205]

I hadn't answered because I wasn't sure. Unfortunately, it occurs each and every time. However, it does not do this when returned back to stock.

I wish I knew where to look but the truck is still getting me to and from work so. It's only an annoyance right now.

[svt2205]

Thought I'd follow up on my last post. This problem seems to have fixed itself. I now think I filled up with a load or two of crappy gas. I do now notice some very minor pinging but I would think our local fuel suppliers are still pumping the lower BTU winter grade fuels.

Thanks for those who tried to help.

[Jackpine]

Minor pinging shouldn't hurt, but I still don't like it. You COULD retard the spark by 0.25 degrees, which would probably get rid of it (and shouldn't cost you much in power). I wonder if you're running slightly lean? That can cause pinging too.

- Jack