Have you checked the IAC motor? Check the EGR for a vacuum leak too.

 

98 could be TBW but most of them are cable driven. You can check the TPS also with an OHM meter, the older analog ones work best for this since they are more sensitive to dead spots in the TPS resistor inside. Just find the 2 posts that will read the resistance from the wiper to the resistor and then slowly move the TPS. The needle should move without jumping as you open the throttle. If it jumps up or down then you have a bad TPS. You can also use a digital Ohm meter to do the same check but you need to use one that has a very high sample rate or the numbers will be jumpy anyway.

Massey