So I had the D4 light blinking I pulled up the code and figured it out with your guys help. Came out to be the solenoids on the trans. I replaced them today on my 93 accord lx automatic F22A1. Took it for a test drive and the D4 light blinks intermittenly. I try to pull up a code but when I try nothing blinks the CEL or the D4. The D4 sometimes blinks when I'm going under 50mph then stops when I hit 50 plus. It sometimes starts to blink when I activate the turn signal then after deactivating the signal the D4 light continues to blink. I'm thinking it has something to do in the gauge cluster but I'm not sure. Also while in drive if I activate the turn signal the tac and speedo jump up and down. I'm really stumped on this one.

 

Strange unrelated electrical problems sound like a bad/loose/corroded ground. The other alternative is a short in the cluster itself.

There should be a block of ground wires grounded through a bracket on the driver's side somewhere above the fuse box (maybe way above and towards the window) that you may want to clean and tighten. They may be a PIA to access.

I don't have a pic of the ground locations on your car, and there may be other grounds that you can check. You might be able to find an inexpensive factory service manual on Ebay. I bought one on a CD for <$20.