I did my first engine replacement, thought it would be a head gasket, block was cracked. It feels fine when its cold or going slightly downhill - when it is up to temp and is loaded at all, it will loos power feels like a clutch is being pressed and speed slows for 60 to 40 and it begins to slow while the transmission up shifts like it would if it were gaining speed. The codes say PO135 & PO155 Heater Circuit O2 sensors (but they cant all fail at the same time can they?) , PO403 EGR Recirc and PO443 EVAP Canister Solenoid. I've attempted to do it myself just to say i did it, however, it has been off the road too long now. I'm resorting to a $130 Diagnostic at the Ford Dealer soon if I don't figure something out. _ I think it may be electrical shorts in the harness or connectors or a vacum problem? How to I go about eliminating these possibilities?

 

As it turns out I replaced the old tranny fluid with new which f'd up the whole thing. Expensive lesson to learn. About $2K. Had it rebuilt, replaced the catalytic converters and it ran great for over a year.