Rpm speedometer needles drop
 

Okay so this has been very aggravating and idk what to try but here is the problem I'm having. While driving my rpm needle and mainly my speedometer drops down to 0 then trys to jump back up to where its suppose to be but fails so it just bounces around mainly when it's hot cuz it dont do it right off the bat when u take off only after few mins of driving. Here's the funny part I have no check engine codes my alternator and battery is fine I did have a engine code show first day I noticed it said was a misfire on 4 but that went away quick idk what to do I figured the speed sensor but that would give engine code right and not cause my rpm to do the same but overall my car drives just fine so idk what it could be

What year is your accord?
When you say both Tach and speedo needles drop to zero and then bounce around, does the engine continue to run normally?
(note: what you read on the cluster is different than what the ECU reads from its sensor feeds)

Check that both battery terminals are clean and tight.
Check that the car's grounds (thermostat housing on engine, transmission, valve cover/head. and body) are clean and tight.
Use electrical contact cleaner to clean the connections to the dash cluster. (disconnect the connections and clean them)

My old 1991 CRX Si had a faulty ground connection to the cluster (too many previous owners; one of them screwed up the harness plug to the cluster; the ground pin in the connector plug was only connected by a few strands instead of the full wire; I pulled the pin, uncrimped its connection, added a 1" tail, then reconnected that to the ground with a small crimp connector). Sold the CRX Sept 2014. (too tricky getting it smogged and finding parts.)

take care,
ChrisS

When my car gets warm it's only when its warm that it does it. But the needles starting with speedo drop below speed I'm going then try and go back to the speed . when my radiator was busted it was going to zero and resting there. car drove no different when needles at zero or when they working I've checked my main connections and alternator I'm about to get test the cruise control the part that tricks me the most is that it only happens when the car is warm . And it was worst when my radiator was leaking

test
 

This is a brief test of posting, please ignore.

Check the ground on the thermostat housing. Look at wiring connections that might have gotten wet when your radiator failed.

take care,
ChrisS