So every now and then when the cars been running for a bit, the speedometer will stop working and the D4 light will start flashing and sometimes the tranny slips. I've scanned the OBD1 codes and heres what i found:
* 3 MAP - manifold absolute pressure sensor
* 17 VSS - speed sensor
* 21 VTEC spool solenoid valve
What should i do from here?

 

i checked the other codes and heres what i found
ABS:
* 18

Tranny:
* 1
* 3
* 4
* 8
* 13
* 14

 

Unless the harness has been damaged, or the car flooded, I doubt the transmission has all those issues.

Check your main bonding grounds.
Verify battery is fully charged and can hold a proper charge.
Verify battery terminals are clean and tight, battery cables are in good condition.
Verify bonding jumper on engine mount is installed, and mounted correctly.
Verify engine bay grounds are clean and tight.

Speedo does not work as the VSS is either damaged or disconnected.
I'm thinking a ground on the engine/trans harness is loose corroded or damaged.

Tried to send a PM but not allowed.
Link to FSM are not allowed to be posted on the forum per rules.