My path finder only reaches 100 kilometeres per hour and drives real sluggish, what is most likely to be the problem?

1989,
100k sounds like the very old , smog timer , in fact a real clock
so when it makes noise, unplug it. end story.
id need country car was sold to, to be accurate,
is this a speed limit, 100 KPH? 100 kilometer per hour?
if yes, it might have a unified alarm module.
the FSm covers this well, get one see the schematics.
if unified, killing one alarm , kills all. pulled, i dont know how you'd like that.
on some cars the alarm is deep in the cluster ,very hard to get if at all.

buy the factory service manual, scan and post this page.
alarm module.

Have an electronic evaluation carried out, it's quicker and in the long run safes you frustration and cash.

So, have you had the problem again? If so, what did you find to be the solution? If you tell us, then it could help someone in the future, thanks.

Could be many things. Do you have a check engine light on? If so get it diagnosed. However I doubt that you have this condition as it sounds like you take quite good care of your car. Some other less obvious things to check, are tire inflation, and have the car raised on a hoist, and checked for a binding brake.That is quite often overlooked. Have a reputable garage drive the car with a scanner hooked up, and have them check that all of the sensors(ie. coolant and ambient air temp, etc) are within range.

i would replace fuel pump and see if this helps. as I am sure it runs fine when it is cold but when it gets hot it backfires and is real sluggish.

odd... sounds like the turbo has some sensor built in that cuts it off, do u know if other golfs have something like that? Could be a heat triggered mechanism or a backpressured one? have you modified intake path at all? egs boost controller, Blow off valve, Wastegate, intercooler?

in the center in front of axle

Check wheel balance,
check steering linkages for loosness - such as tie rod ends, steering rack linkages etc,
check driveline for worn/loose joints and bearings.

$100 approx cost for part. Go to (repairpal.com) enter your info & pick replace starter, and it will give you price for your area by zip code.

check the sparkplug wires on the firewall side for arching-body seam there that will cut them