Without more details and unless I had a similar truck, I chose to go to one of the more common speaker manufacterers of Jensen. Using the basic fact of 1990 Toyota pickup, I came up with this.
http://retailer.installationexcellen...6-30F17075C5BA
Not sure if you were to do the installation yourself, but another simple choice is to go to a car stereo dealership and have them recommend what speaker could be used. You're not obligated to buy from them, but it's possible they could make you a reasonable offer. If the door is already wired for speakers, you would simply mount replacement ones. However, if you only have the dash ones you are complaining about, perhaps a car stereo dealer might be worth the extra labor and quickness in time to get new speakers in, don't you think?
Good luck.