I overheated on the way into work yesterday during stop and go traffic. Managed to coast into work. Got home and the fan seems to work, so replaced the reservoir cap, thermostat and water pump. While in normal driving conditions it seems to run cooler than it did before. On my way in this morning it almost passed the A. What else should I be checking or swap out to fix the issue?

 

Radiator flush should help.

 

I just change the radiator about 6 months ago. The coolant was clean when I drained it too

 

I wouldn't have changed the water pump.
Stop and go issues are fan related in my opinion.The fan motor,sensor,relay.

 

Tested the fan. High and low speed come on when voltage is applied. When it got hot the fan was on so im at a lost. Could that still be the sensor or relay module?

 

SOLVED! When my fan seized up about a year ago I went to a local mustang salvage yard and asked for a fan for my 96. He gave me one from a 98 thinking it would fit. Got it home, tried to install it and nothing would line up right. I called em up and he insisted that it should be the same fan from 96-98. I had no way back and the mustang is my only ride so i hacked it up a bit to make it fit. After having my heat issues recently I started looking at fans online and noticed that they ran 94-96, wtf? Went back to the salvage yard last night, picked up a fan for a 95 and sure enough it fit! No more heat issues

 

Good news.
Back in the old days,I went through the same stop and go overheating thing,while it was fine at highway speeds.It had me perplexed,especially since my mechanic told me that the fan clutch was ok.Since I had exhausted other avenues,I went ahead and put a new one in.Problem solved.