Still chasing a miss in the fury suburban 400

Dodgeguy,
I am leaning more towards a vacuum leak now, as I replaced my distributor and re-timed the engine (my old distributor had some shaft play anyway). If I unhook a vacuum line it runs worse, but if I hook it back up it runs decent for a second or two then right back to random missing. Once the temperature is steadily warm out I will attack it again. I currently have the brake booster line plugged off because the bladder in the brake booster is ripped or broken so if its hooked up it causes a major vacuum leak (once I get $170 I will order a rebuilt one). I may just plug the lines off at the carb. and see what happens.

 

There are lots of places you can have a vacuum leak besides the carb lines. The vacuum tree, carb base, intake are the most common, besides a bad hose.

 

Well, still got the miss. Here is a video of what she is doing:

http://www.youtube.com/watch?v=tcSW-Z_j94A&feature=youtu.be

 

I just realized that my above post is for the wrong thread....my apologies.

 

Have you checked to see if the EGR is stuck open? Does not sound all that bad.

 

These old ears couldn't even hear it. But, then, when you held the camera steady on the passenger side, I could see it and then hear it in sync with the shake. I, almost always, have to be there to see and hear a slight miss in an engine. It doesn't sound too bad, but, it is there and would bother me too. A miss like that and the one Jase and Swanny describe in their respective cars could be so MANY different things that it is really, really difficult to diagnose from a distance. I'm hoping that a Mopar guy with experience with this 400 engine, and maybe even with the same problem, will see this thread and chime in with a solution. Does it miss under load? Consistently & rhythmically?

 

Silverfox,
The random missing you see in the video is pretty much what it does all the way up from idle. Under load it still does the same thing. I haven't driven it on the street yet because it really needs a brake booster (she's heavy) otherwise in a panic situation you need to double foot the brake. I will be getting a booster in a week or so and was trying to get this miss figured out so I can get her on the road, first time since 1990 when it was parked by the original owner. I've seen the car as long as I can remember, and I've seen another neighbor messing with it years ago and I was hoping they couldn't get it running lol. But now she's mine, ready to be awakened on the open road again. Thanks again. It's a tough thing to figure out, I know a manifold leak will produce similar symptoms.

 

Well...get it on the street and drive it like you stole it for awhile. That miss may disappear. Could be a carbon issue. At least then you will know...one way or the other.

 

I caught a miss this way and made her my missus. When you catch her, let us know!

 

Has this been solved yet? My friends 440 had the same problem. Turned out it was the plug wires he had bought new from NAPA. He put on an old set and it runs fine. Plug wires are always vulnerable on B & RB blocks because of the manifold heat and routing.

 

Why do ya think they were named Fury?
When you can't fix 'em, it makes you 'Furyous'!!!!!
HAHA!!