Backfire Problem
 

So these are the details, I don't know if they're all related to one thing, but I'll just give the symptoms and hope people know what I'm talking about.

So this has been happening for about a week and a half. After driving the car for about 10 minutes or so, if my RPMs are relatively high, when I let go of the accelerator to decelerate, my FD shakes a little, and I start getting grumbles and minor backfires from the exhaust. Also, driving in stop and go traffic makes this happen ALOT, and it feels like the ignition is going to shut off after this has been happening in traffic for a while. Also, since this has been happening, the car feels a bit sluggish, and slow to move from stopped. I'll also mention, at higher speeds, the car runs fine.

Hope people know exactly what is wrong, and not everyone give a different answer... But thanks in advance for any help!

I had something similar happen to me when one of my injector o-rings went bad and was dumping raw fuel past the injector and into the motor. It would be fine at high rpm, but at low rpm the moment I let off the throttle it would back fire like crazy and it ran like crap. Have you recently removed the injectors for any reason?

I suppose it could also be a ignition issue but this was what happened to me.

I was thinking the dashpot, and idle screw. Also how are the grounds on the car?

Grounds look fine. But how could it be the grounds that was causing this problem? Which grounds in specific?

I got this problem when I started running the 850cc in the primary position. My theory is that the 850s are not so good at metering fuel during low speed and so it dribbles and BAM, BAM, BAM, I get a few back fire when I drop the throttle.