Carbureted car stalls out after complete stop

[Evan]

Alright, don’t hate on me here. I’m relatively new to carbs but have a bit of experience. The stock 7200 I had on called it quits on me. That’s the only reason I took it off.

So some details:

The car is a 1985 Mercury Grand Marquis. The carburetor has been swapped from the stock 7200vv to a Holley 2bbl 350CFM with a Manual Choke. I’ve had it at two mechanics while I was out of town and the timing was set and carb adjusted. The only thing I can think of is not all vaccuum lines were used in the end, as some lines no longer had a place to go on the new carb as compared to the old carb. This led to the EGR valve not being hooked up, which is the most notable thing I can think of. Other than that, no other essential things are missing.

The car is usually fine if I’m driving it around town. But once I get on or off the highway is where the troubles begin. Say I’ve just driven 100km/h on the highway for an hour and take an exit to go back to town, the first stoplight I come to a complete stop at my car will stall or otherwise be extremely sluggish.

Along with this problem, sometimes the car will shudder or have poor acceleration when trying to reach highway speeds. This doesn’t happen constantly, it comes and goes.

I have the EGR port capped off, and all other non-attached lines plugged. Could the EGR really be the problem? Or is there something I’m missing?

Topic

[Jim]

The EGR valve must be hooked up and the valve needs to be working properly.

[Author]

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