Hey guys was wondering if anybody could help me i have an early 99 f250 7.3 with a bad torque converter since i bought and since i dont know how long it was bad i was just gonna run it till it kills the trans the truck has 110,000 mi. And on the last hual were i was towing a 24 ft trailer and it started to make a hissing on acceleration and the hissing holds steady when i stay at a constant speed then i also notice the rpms surge up about 500 rpms when holding low speed and decreases once its at highway speed my mods are tymar intake,4" turbo back exhuast and a ebpv free turbo pedestal and i just replaced the fuel filter so its not that any help is appriciated cuase i need my truck on the road and thank you in advance for any help

 

sounds like u have a boost leak or exhaust leak...time to start the search