Sudden RPM Surge

[asburydan]

My '95 GT sometimes has a sudden surge in RPM, and you can feel and hear the engine surge. The surge stops on its own. Sometimes it happens 2 or 3 times in a row an sometimes it happens once. It mostly happens at 50 -65 MPH. It happens maybe once every 3 or 4 weeks. I use Tectron fuel system cleaner every couple of months. Any ideas about what could be causing the surges?
The first time it happened the car surged, and I thought it might be the transmission (AT), but had the trans thoroughly checked and it was fine. Thanks.

 

[86hybridGT]

Maybe your IAC is going bad or dirty or could be something else. That's the first thing I'd try. I am working on my 94 right now witha surging issue. There is also a thread on it here at stangnet. Search for surge or surging.

 

[HISSIN50]

Are there any trouble codes stored?

 

[asburydan]

Sudden Surge

After some checking with mechanics, it is looking like it might be torque converter problem. Seeing transmission guy next week. No touble codes stored.