Focus 2001 1.6 Zetec Speedo Erractic

[petesfocus]

Had the speedo dropping to zero problem for a year and finaly decided to fix it as symptoms seemed to be getting worse. After struugling for what seems hours, got the vss out and replaced. Since completing this it hasnt dropped to zero again.

Also changed oil, filter and air filter at same time. Notice the crankcase emmision hose was collasping when car was idling so replaced that too. Also had a vacumn leak which was fixed with a new pipe.

Now however my speedo jumps upwards with a momentarily change in power felt. Unsure as to what to look at next, also may be relavent is im 50 % sure i can hear another air leak but cannot locate it. I can hear it strongest between air filter and coil. Ive sprayed pipes with carb cleaner to try to identify.

Any suggestions that dont cost the earth appreciated.