Suddenly running rough

[Mako21]

Hi guys. Around two years ago you all helped me get my first classic car, a 1976 dart, running great. It now has developed an issue I can’t quite fix.

I’ve lashed the valves to factory spec, replaced the ECU, cap/rotor/plugs, fuel filter and checked timing to 8 degrees. I rebuilt the carb two years ago. I blew on the fuel hose to check if the gas tank screen plugged. All ok. Fuel pressure ok too, it’s pumping hard.

It cruises fine and no bogs off acceleration, but as I come to a stop it will misfire and run rough. Also, when I make turns to the left it will stumble like it’s about to shut off. Also just now I realized if I shake the car side to side left and right really aggressively it runs really rough and then cleans up once I stop swaying it side to side. The idle is inconsistent. It’s driving me crazy because when I try to diagnose it idles great and then I drive it and it runs rough.

Any ideas? Any help appreciated.

 

[mbaird]

pull your carb and check for debris?

 

[CFD244]

Float level?

 

[elvaliant66]

Gonna be your carb. Needs a freshening up . Has the gas tank ever been replaced? From my experience anytime you get a bog or rough conditions when your turning it’s related to carb. Could be debris, could be float level . Check the accelerator pump . When turning- it bogs when you hit the gas to pick up speed again right? Or mostly when you let off the accelerator?

 

[Mako21]

I’m working on it now since I’m off for the long weekend. I hooked up a vacuum gauge and it is reading steady at 21hg at idle, 800 rpms.

What I am noticing though now is the idle mixture screw I turned it all the way in seated and it does not kill the engine. Turning it out does conch and kill it and it get real rich smell. Also to get a baseline I set the timing down to 2 BTDC degrees and drove it and it idles better than where I had it originally at 8 degrees BTDC.

 

[Mako21]

The bog happens while in the left turn and initially straightening up out of it, and then once fully established straight it cleans up and accelerates and cruises great.

 

[elvaliant66]

The bog happens while in the left turn and initially straightening up out of it, and then once fully established straight it cleans up and accelerates and cruises great.

Yea I’ll check the carb. Look for debris and recalibrate the float. 50 bux gets you a new carb kit .

 

[volaredon]

$50 for a 1 bbl carb kit these days? Yikes. Last one I bought was like $18