new engine, car miss fires during normal driving

[RazorbackGT]

I just installed a remanufactured engine in my 85 GT. I deleted the smog pump but still have the EGR just capped the vacuum port on the valve. I have an Edelbrock 1406 and stock EGR intake. Installed new headers and clutch. Car has good power under acceleration but when trying to drive under normal traffic conditions car miss fires and bucks. I've tried adjusting the timing and seems to have no effect on problem. I hooked a vacuum line back up to EGR and no effect. I have distributor Vac advance hooked to passenger side port on carb. Car starts and idles fine, just like I said, normal driving it's missing and cutting out but as soon as I give it a little more gas it straightens right out.
I'm thinking of changing step up springs on carb but really don't think this is the issue, any ideas?
Thanks,
Brant

[Walking-Tall]

This is idle/off-idle fuel mixture territory. Edelbrock carburetors have 2 idle feed restrictions per primary barrel on the way to the idle screws and discharges, but more importantly to your situation, the transfer slots... where you are experiencing the misfires/surging/bucking. Sounds like there might be idle feed restriction fuel blockage, dirt, etc... and float level and such sounds fine since you step on it more, into the main circuit, and it's fine...

[RazorbackGT]

I'm thinking it's got to be the EGR. I mean it is acting the exact same as the last motor did before I replaced the EGR valve and it smoothed right out, night and day difference, Does anyone make a non EGR carb spacer that works with factory intake?

[cb84capri]

Easy/free thing to try; move the accelerator pump link a hole closer to the arm's pivot to increase pump shot.

Cale

[RazorbackGT]

I did that first thing and it really helped , eliminated the take off stumble, but what it's doing now is more like when you let off the gas and are coasting in gear it's missing and bucking. As soon as I give it a little gas, smoothes right out. I found Edelbrock non egr spacer I am going to install today to eliminate that possibility and hope it fixes it.
Walking Tall, I am new to carburetors, so if the egr fix doesn't work, should I pull the top off the eddie and spray out with carb cleaner? I am hesitant about messing with the carb too much , I can just see me blasting some air in there and some little part go flying out.

[Walking-Tall]

Off, apart, cleaned, and a rebuild kit installed would be best. I did a 1406 for a guy a few months ago...







... and I can tell you that the Edelbrock rebuild kit (RK1400, $28.99 + $7.45 shipping US) from AllState Carburetor & Fuel Injection ( http://www.allcarbs.com ) is a good one, that includes an ethanol-resistant accelerator pump plunger cup, a steel shaft accelerator pump, and even a quality lid hole seal and star washer type retainer for the accelerator pump.

If you'd rather try a little sumthin'-sumthin' that might help prior to a rebuild, remove the top...



... look for and note any dirt/sediment that might be residing in the carb's basement (this fellow's had plenty)...

... remove each of the primary venturi clusters...





... and see that the bottom pickup tubes' orifices and all passageways throughout them are clear...




Within about the first 8 minutes of this video ("Mike's Carburetors"...no, not me or my video, lol) shows how to get to the primary boosters removed point:




The only "little part/s" up top are the check ball and weight that reside underneath the accelerator pump shooter, which you won't be removing, so no fear. Good luck with it

[RazorbackGT]

Thanks for the good info. I found the problem after replacing EGR spacer with the edelbrock non EGR spacer it was still doing the same, so then I tried the ole carb cleaner trick and sure enough, vacuum leak below spacer. I used the Permatex Ultra Copper to make a gasket between the intake and spacer and worked like a charm.