I have an 87 gl wagon with an EA82 motor in it. i just got it running and driving. i noticed the speedometer lags behind. no matter the conditions its always the same slow lag. after i reach my speed it takes about 5 seconds for it to finally catch up. i cant find anything online about a slow speedo. does anyone on here have any ideas as to whats causing it/how to fix it?

All of mine do this. It's annoying.   I have been using the speed reading on my gps for years.

I has to be gunk or dirt in the needle movement.  I just never spent the time to get in there andand try cleaning one.

check, lube or replace the speedo cable is the easier option of my two suggestions. The second involves getting speedo head out and checking how clean or gunked up its little cogs are and find a white lithium grease (if you did not chuck it out Jono ! ) to apply to the small white nylon cogs and shafts

Mine only does this in summer, even then, it’s random. 

Cheers 

Bennie

Mine runs about 5 miles slower than the speed I'm actually going. I need to have it calibrated. 

Odd thing, when I bought the car new in '86 the speedometer cable broke (!) at 18K miles and had to be replaced. Haven't had to fool with it since but I'm pretty sure if I get pulled over for going 30 in a 25 mph zone no cop is going to accept the faulty speedometer excuse.

You bought it new in 1986 and still got it !! That's impressive !!!

12 hours ago, Steptoe said:

You bought it new in 1986 and still got it !! That's impressive !!!

Yep. Drive it all the time. It gets the garage, my SUV gets parked on the street.

It got a new (OEM) clutch and flywheel recently but could use some work on the synchro. I've been told that the trans. needs to be pulled to do that, which sounds like a lot more trouble (cost, labor-intensive) than it's worth.

My next project for a it is to bring the AC back to life. Have the parts, just need to save $$ for the labor. Not a priority until late spring.

Mine has also started to lag. Seems to be worse now that it's winter. 

Doesn't really bother me, but I have a spare gauge cluster to swap out when spring gets here.

Goodluck!