Read quite a few posts concerning surges. I have a 2004 6.0 F250 has been surging. One mechanic recommended the FICM change but the FICM repair guy was against it. I tried the Hotshot sauce with short term help. Surges returned in 20 miles. I read a post concerning the use of autoenginuity software. I bought the software and after a few sessions of setting up the software and setting up what I needed to monitor concerning the surges, I determined the IPR valve was bad. I Changed the IPR valve and engine has been running smooth. I like the way the software can drop information into a spreadsheet, print it for ease of troubleshooting rather than monitoring multiple gauges at once. Great program. Worth the cash..