1998 Dodge Intrepid Stumble/Stall Issues

I have 1 1998 Dodge Intrepid 2.7L with 44500 miles. It has started to miss/stumble at idle and during acceleration. The idle stumble has progressed into a stall at time when in park and more often when in drive. I can rev the engine slowly to about 2000-3000 rpm and will get more stumbles and after 3000 rpm the engine will run smooth as silk. I hooked up my friends Auto-Xray unit and while the engine was at idle the TPS read 13% and as the accelerator was pressed slowly, the percentage went crazy. I t would fluctuate rapidly. At 3000 rpm and above it would settle out at about 44%. If I did a 1 second WOT in Park, the percentage would not change at all. Always at 13%. I believe that it is the TPS, but since that part costs $110 around here, and I am a poor college student with a family, do not want to spend that much cash unless it is going to fix the problem. If you can put my mind at ease about this, I would really appreciate it! Thanks in advance for any help you can provide!
Dave

Update: I replaced the TPS, but it didn'y help. Also, I am not getting any DTC's.