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Problem with surging while stopped

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77crewcab

1/2 ton status
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Lubbock, Texas
I am having a problem with my truck while in gear and stopped at a light or something it is trying to surge forward. If I press and hold the brake it winds up rocking front to back while stopped any idea what this is caused by? I am also having the lights flicker while at idle speed but shine constant above idle, is this just alt. or something else? Also is there an ID tag on the rear end that shows the gearing without having to pop the diff cover?
Thanks,
Monty
 
Is it just the idle may be too high , or is the motor surging up and down? The idle may be too high if it runs fine in park or neutral. If the engine surges up and down, I'd say vacuum leak or spark/fuel. As for lights, have parts store test alternator and battery. /forums/images/graemlins/k5.gif
 
Surging, not trying to constantly push while on the brake,,,
Since you don't have a profile filled out and anything telling us what kind of setup you are running as far as year, what type of motor whatever, can't really say much, i had this same surging problem when my fuel pump was dying out, I am running a TBI 350.
/forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif /forums/images/graemlins/dunno.gif

If the lights are surging with the motor, as in low power when idle is on the low side of the surge, then yes, it's just the fact that the motor is running rpms down too low for the alt to give out adequate charge.
 
if your engine is not surging i have had my clutched in my transmission do this but it acts like it is actually trying to jump forward then sit still for a sec or two and jump forward again. it was a th350 tranny in an el camino. hope this helps.
 
Sorry here is the info on the truck 77 3/4 crewcab 454/th350 with holley 4bbl 600cfm. Lets see if I can be more clear at idle in park the engine seems to rumble like a large cam or actually like a Harley (Dun,dun, dun, dun, Dun, dun, dun etc) and the lights flicker slightly. When revs are applied lights brighten and get steady engine sounds still sounds like a Harley being revved up. The "surging" I am talking about is while in gear and stopped for a stop sign or light, the truck rocks front to back as if it is trying to over power the brakes. Does this help? I am new to the whole carb world and could use some help on how to adjust the idle and tune the carb if that is the problem, I know the gas mileage is about 7-9 mpg or worse ( speedo gear needs replaced) Please help school me on the carb topic.
Monty
 
Should I start by replacing all the vacuum hoses or is there something else I can do to test for vacuum leaks?
 
On those older rides you can use carb cleaner very lightly around things to check for leake, try to keep it away from the distributor though, as it can, and will ignite if the conditions are right, ( /forums/images/graemlins/doah.gifexperienced /forums/images/graemlins/doah.gif), just spray around the carb gasket and lightly around hose fittings, look for bad and cracked hoses, you also can "usually" hear a pretty good vacuum leak just a hissing noise slightly different that the carb noise.
 
what about staring fluid? I've got some here is why I ask. Also what all should be connected with vacuum hoses (i.e. pvc, brake booster any thing else?) About how much for new vacuum hoses?
 
That'll work, but is m uch more dangerous that carb cleaner, blows up quicker and much easier. I personally wouldn't use it.
 
My engine seems to idle too high when it warm but when I tap on the gas slightly it settles down. ANy idea what it could be???

P.S. Sorry about jacking the post.

Eric
 
After spending some time looking over the engine I have found out a few things that might be the cause for my problems, let me know what you think. I still haven't checked on the vacuum leak but plan to replace all hoses to make sure they are good. Can someone tell me where to find a vacuum hose diagram for a 77 3/4 454 with no emissions?

Okay I knew that this was a truck origionally with a 350 but had a 454 put in. I see that the engine is an emissions controllen engine with the egr blocked off on the manifold the vacuum switch in the t-stat housing and a pcv valve. Also the Holley carb turns out to be model O-1850-3 which is a 600cfm carb. A 454 needs at least a 750 cfm right?

Here are my plans: replace the intake,carb, and cam with Eddlebrock performer package and replace valve covers. Any other suggestions? Looking for good daily driver with ocaisional towing so I am looking at the idle to 5500 package. Also I notice that there is a black round plastic "can" looking thing on the pass side by hood hinge that is connected to the vacuum system can anybody tell me what it is?
 
That carb should sell on Ebay or here to help get some money for build. The Edelbrock idea is fine for a driver/tow rig. Personally I don't like those carbs on side hills etc. As for the emissions and hose, if you need to pass smog(don't know with a crewcab, is it high GVWR?) where your at , some of it will need to stay. That round can is a vacuum resevoir, usually runs from manifold to a/c controls. Hope it helps /forums/images/graemlins/thumb.gif /forums/images/graemlins/k5.gif
 
The truck is smog exempt due to age and weight but I don't have smog regs to deal with in this part of Texas anyway. What do you mean about the hills this wont see any off road use cause it is 2wd so will the performer package work well? Any info about where to find a vacuum diagram?
Thanks
Monty
 
Will work just fine on a 2wd application, Paul doesn't like the Edelbrock carbs cause i loand him one a long time ago, and it wasn't setup for offroad use, the float bowls or whatever weren't setup, so it would stall out on him with a good incline situation. /forums/images/graemlins/doah.gif

A buddy of mine has one on his 2wd 350, damn thing is fast too, well along with other mods. /forums/images/graemlins/smirk.gif
 
I think I have some vacuum diagrams on hard drive at home I will look. If your not needing smog then it would be easier. I'll look when I get home unless someone else gets to it first. /forums/images/graemlins/k5.gif
 
Thank you very much! I don't need the smog cause I don't have it in my area and this is a smog exempt vehicle anyway. I has the 454 now but origionally had the 350 if that makes a difference. I see lots of loose vacuum hoses and vac ports unplugged but don't know what is needed and what was for the smog stuff on the 454 origionally. From what I can tell though most 454 came with 750 carb so alot of the problem may be that it is choking with just a 600 on it.
 
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