Engine staggers when given throttle

[payrus]

I have a 69 C10 with 350 motor. It will idle all day fine but when I drive it the engine cuts out almost like it is giving out of gas. what could be the problem?

[68gmsee]

Several causes. There's no magic bullet on this one so try the easiest first.

Check choke adjustment if it happens primarily when engine has not reached operating temp.

Make sure vacuum advance is working by using mouth suction to see if it moves and has no leaks. Try changing it to manifold vacuum if you have it to ported vacuum.

Check vacuum with vacuum gauge and adjust idle air adjusting screws for max vacuum.

If you have HEI check timing and bump it up to 12 deg.

Check the throttle pump to make sure it squirts gas when throttle depressed by hand.

Other fuel related possiblities like clogged filters or restricted fuel flow.
Carb needing a good cleaning.

As a last resort do a search of "quadrajet stumble off idle" either on this site or on google and you should get some hits.

[hugger6933]

Is the motor hopped up at all? does it have a factory type carb or is it a Holley? If it is a Holley I think you have a blown power valve as they are pretty darn sensitive to the bacfires and that cause them to blow out quite easy. When you drive this truck does it start chokeing down under a steady throttle as well like a flat striat roadjust constant throttle? What type of exhuast do you have? A exhuast obstuction will choke your motor down as well. Iknow these are the unlikely ones , I am trying to think off the wall so my idea can be last resort ones to check. Jim

[domeier]

in my own humble experience, 99 out of 100 stagger/stumble problems are caused by vacuum leak. Make a map of all the vacuum lines and start plugging them off one by one until you find the culprit. Also, check the carb to manifold gasket - I had one get part sucked in once, took me forever to find out what was going on.

[Wrenchbender Ret]

If it is like a hesitation it is very likely the accel. pump in the carb. If it is kind of a stumble it can be bad spark plugs or plug wires.

[Square_78]

I went through this mess last year and it took a while to figure it all out. I replaced a LOT of stuff and what solved it in the end was removing the second fuel filter down on the frame rail just before the manuel fuel pump. Apparently those pumps are ment to push and not pull to the filter was blocking the flow of gas. I still have a good filter up by the carb. I have a new gas tank and new fuel lines so I am fine with one filter. I am going to upgrade to a better fuel pump later on sometime as my stock ones performance is probably borderline for my engine.

[tommys72]

[QUOTE=68gmsee;5799144]Several causes. There's no magic bullet on this one so try the easiest first.

Check choke adjustment if it happens primarily when engine has not reached operating temp.

I like this answer...mine does it too, but only until it warms up, then it runs great
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[payrus]

not to sound dumb but how do i check the choke adjustment on holley carb. I did see that my electric choke wire was not hooked up.